#LyX 2.2 created this file. For more info see http://www.lyx.org/
\lyxformat 508
\begin_document
\begin_header
\save_transient_properties true
\origin unavailable
\textclass book
\begin_preamble
\usepackage{wrapfig}
 \setlength{\intextsep}{0cm plus1cm minus1cm}
\newcommand{\menuitem}[1]{\textbf{\emph{#1}}}
\end_preamble
\use_default_options false
\maintain_unincluded_children false
\language american
\language_package default
\inputencoding auto
\fontencoding global
\font_roman "default" "default"
\font_sans "default" "default"
\font_typewriter "default" "default"
\font_math "auto" "auto"
\font_default_family default
\use_non_tex_fonts false
\font_sc false
\font_osf false
\font_sf_scale 100 100
\font_tt_scale 100 100
\graphics default
\default_output_format default
\output_sync 0
\bibtex_command default
\index_command default
\paperfontsize default
\spacing single
\use_hyperref false
\papersize a4paper
\use_geometry true
\use_package amsmath 1
\use_package amssymb 1
\use_package cancel 1
\use_package esint 0
\use_package mathdots 1
\use_package mathtools 1
\use_package mhchem 1
\use_package stackrel 1
\use_package stmaryrd 1
\use_package undertilde 1
\cite_engine basic
\cite_engine_type default
\biblio_style plain
\use_bibtopic false
\use_indices false
\paperorientation portrait
\suppress_date false
\justification true
\use_refstyle 0
\index Index
\shortcut idx
\color #008000
\end_index
\paperwidth 14cm
\paperheight 14cm
\leftmargin 1cm
\topmargin 1cm
\rightmargin 1cm
\bottommargin 1.2cm
\secnumdepth 2
\tocdepth 3
\paragraph_separation indent
\paragraph_indentation default
\quotes_language english
\papercolumns 1
\papersides 2
\paperpagestyle plain
\tracking_changes false
\output_changes false
\html_math_output 0
\html_css_as_file 0
\html_be_strict false
\end_header

\begin_body

\begin_layout Standard
\begin_inset ERT
status open

\begin_layout Plain Layout


\backslash
thispagestyle{empty}
\end_layout

\end_inset


\end_layout

\begin_layout Standard
\begin_inset VSpace 0.2in
\end_inset


\end_layout

\begin_layout Standard
\align center

\size giant
expEYES-17
\end_layout

\begin_layout Standard
\align center
\begin_inset Graphics
	filename pics/eyes17-nb.jpg
	lyxscale 10
	width 6cm

\end_inset


\end_layout

\begin_layout Standard
\align center

\size large
User's Manual 
\end_layout

\begin_layout Standard
\align center

\size largest
Experiments for
\begin_inset Newline newline
\end_inset

 Young Engineers and Scientists
\end_layout

\begin_layout Standard
\align center
http://expeyes.in
\end_layout

\begin_layout Standard
\align center
from
\end_layout

\begin_layout Standard
\align center
PHOENIX Project
\begin_inset Newline newline
\end_inset

Inter-University Accelerator Centre 
\begin_inset Newline newline
\end_inset

(A Research Centre of UGC)
\begin_inset Newline newline
\end_inset

New Delhi 110 067
\begin_inset Newline newline
\end_inset

www.iuac.res.in
\end_layout

\begin_layout Standard
\begin_inset Newpage newpage
\end_inset


\end_layout

\begin_layout Standard
\begin_inset ERT
status open

\begin_layout Plain Layout


\backslash
thispagestyle{empty}
\end_layout

\end_inset


\end_layout

\begin_layout Standard
Preface
\end_layout

\begin_layout Standard
The PHOENIX (Physics with Home-made Equipment & Innovative Experiments)
 project was started in 2004 by Inter-University Accelerator Centre with
 the objective of improving the science education at Indian Universities.
 Development of low cost laboratory equipment and training teachers are
 the two major activities under this project.
 
\end_layout

\begin_layout Standard
expEYES-17 is an advanced version of expEYES released earlier.
 It is meant to be a tool for learning by exploration, suitable for high
 school classes and above.
 We have tried optimizing the design to be simple, flexible, rugged and
 low cost.
 The low price makes it affordable to individuals and we hope to see students
 performing experiments outside the four walls of the laboratory, that closes
 when the bell rings.
\end_layout

\begin_layout Standard
The software is released under GNU General Public License and the hardware
 under CERN Open Hardware Licence.
 The project has progressed due to the active participation and contributions
 from the user community and many other persons outside IUAC.
 We are thankful to Dr D Kanjilal for taking necessary steps to obtain this
 new design from its developer Jithin B P, CSpark Research.
\end_layout

\begin_layout Standard
expEYES-17 user's manual is distributed under GNU Free Documentation License.
\end_layout

\begin_layout Standard
\begin_inset space ~
\end_inset


\end_layout

\begin_layout Standard
Ajith Kumar B.P.
 
\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset

(ajith@iuac.res.in) 
\begin_inset space ~
\end_inset


\begin_inset space ~
\end_inset

http://expeyes.in
\end_layout

\begin_layout Standard
V V V Satyanarayana
\end_layout

\begin_layout Standard
\begin_inset Newpage newpage
\end_inset


\lang english

\begin_inset ERT
status open

\begin_layout Plain Layout


\backslash
pagenumbering{arabic}
\end_layout

\end_inset


\lang american

\begin_inset CommandInset toc
LatexCommand tableofcontents

\end_inset


\end_layout

\begin_layout Chapter
Getting Started
\end_layout

\begin_layout Section
Introduction 
\end_layout

\begin_layout Standard
Science is the study of the physical world by systematic observations and
 experiments.
 Proper science education is essential for cultivating a society where reasoning
 and logical thinking prevails and not superstition and irrational beliefs.
 Science education is also essential for training enough technicians, engineers
 and scientists for the economy of the modern world.
 It is widely accepted that personal experience in the form of experiments
 and observations, either carried out by students or performed as demonstrations
 by teachers, are essential to the pedagogy of science.
 However, almost everywhere science is mostly taught from the text books
 without giving importance to experiments, partly due to lack of equipment.
 As a result, most of the students fail to correlate their classroom experience
 to problems encountered in daily life.
 To some extent this can be corrected by learning science based on exploration
 and experimenting.
 
\end_layout

\begin_layout Standard
The advent of personal computers and their easy availability has opened
 up a new path for making laboratory equipment.
 Addition of some hardware to an ordinary computer can convert it in to
 a science laboratory.
 Performing quick measurements with good accuracy enables one to study a
 wide range of phenomena.
 Science experiments generally involve measuring/controlling physical parameters
 like temperature, pressure, velocity, acceleration, force, voltage, current
 etc.
 If the measured physical property is changing rapidly, the measurements
 need to be automated and a computer becomes a useful tool.
 For example, understanding the variation of AC mains voltage with time
 requires measuring it after every millisecond.
\end_layout

\begin_layout Standard
The ability to perform experiments with reasonable accuracy also opens up
 the possibility of research oriented science education.
 Students can compare the experimental data with mathematical models and
 examine the fundamental laws governing various phenomena.
 Research scientists do the same with highly sophisticated equipment.
 The expEYES ( expEriments for Young Engineers & Scientists) kit is designed
 to support a wide range of experiments, from school to post graduate level.
 It also acts as a test equipment for electronics engineers and hobbyists.
 The simple and open architecture of expEYES allows the users to 
\shape italic
develop new experiments, without getting into the details of electronics
 or computer programming
\shape default
.
 This User's manual describes 
\shape italic
expEYES-17
\shape default
 along with several experiments, there is also a Programmer's manual available.
\end_layout

\begin_layout Section
The equipment
\end_layout

\begin_layout Standard
ExpEYES-17 is interfaced and powered by the USB port of the computer, and
 it is programmable in Python.
 It can function as a low frequency oscilloscope, function generator, programmab
le voltage source, frequency counter and data logger.
 For connecting external signals, it has two spring loaded terminals blocks,
 one for output signals and another for inputs, as shown in figure 
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:The-ExpEYES-toppanel"

\end_inset

.
 The software can monitor and control the voltages at these terminals.
 In order to measure other parameters (like temperature, pressure etc.),
 we need to convert them in to electrical signals by using appropriate sensor
 elements.
 The accuracy of the voltage measurements is decided by the stability of
 the 3.3V reference used, it is 50ppm per degree celcius.
 The gain and offset errors are eliminated by initial calibration, using
 a 16bit ADC.
 Even though our primary objective is to do experiments, you are advised
 to read through the brief description of the equipment given below.
 The device can be also used as a test equipment for electrical and electronics
 engineering experiments.
\end_layout

\begin_layout Paragraph*

\shape italic
IMPORTANT : 
\end_layout

\begin_layout Standard

\shape italic
The external voltages connected to ExpEYES17 must be within the allowed
 limits.
 Inputs A1 and A2 must be within 
\begin_inset Formula $\pm16$
\end_inset

 volts range and Inputs IN1 and IN2 must be in 0 to 3.3V range.
 Exceeding these limits may result in damage to the equipment.
 To measure higher voltages, scale them down using resistive potential divider
 networks.
\end_layout

\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open

\begin_layout Plain Layout
\align center
\begin_inset Graphics
	filename pics/eyes17-panel.jpg
	lyxscale 70
	width 10cm

\end_inset


\end_layout

\begin_layout Plain Layout
\begin_inset Caption Standard

\begin_layout Plain Layout
The ExpEYES17 top panel showing the external connections.
 
\begin_inset CommandInset label
LatexCommand label
name "fig:The-ExpEYES-toppanel"

\end_inset


\end_layout

\end_inset


\end_layout

\end_inset


\end_layout

\begin_layout Subsection
External connections
\end_layout

\begin_layout Standard
The functions of the external connections briefly explained below.
 All the black coulored terminals are at ground potential, all other voltages
 are measured with respect to it.
\end_layout

\begin_layout Subsubsection*
Outputs:
\end_layout

\begin_layout Paragraph*
Constant Current Source (CCS) : 
\end_layout

\begin_layout Standard
The constant current source can be switched ON and OFF under software control.
 The nominal value is 1.1 mA but may vary from unit to unit, due to component
 tolerances.
 To measure the exact value, connect an ammeter from CCS to GND.
 Another method is to connect a known resistance (~1k) and measure the voltage
 drop across it.
 The load resistor should be less than 3k for this current source.
\end_layout

\begin_layout Subsubsection*
Programmable Voltage (PV1) : 
\end_layout

\begin_layout Standard
Can be set, from software, to any value in the -5V to +5V range.
 The resolution is 12 bits, implies a minimum voltage step of around 2.5
 millivolts.
 
\end_layout

\begin_layout Paragraph*
Programmable Voltage (PV2) : 
\end_layout

\begin_layout Standard
Can be set, from software, to any value in the -3.3V to +3.3V range.
 The resolution is 12 bits.
\end_layout

\begin_layout Paragraph*
Square Wave SQ1: 
\end_layout

\begin_layout Standard
Output swings from 0 to 5 volts and frequency can be varied 4Hz to 100kHz.
 All intermediate values of frequency are not possible.
 The duty cycle of the output is programmable.
 Setting frequency to 
\begin_inset Formula $0$
\end_inset

Hz will make the output HIGH and setting it to 
\begin_inset Formula $-1$
\end_inset

 will make it LOW, in both cases the wave generation is disabled.
 SQR1 output has a
\series bold
\shape slanted
 
\begin_inset Formula $100\Omega$
\end_inset

 series resistor
\series default
\shape default
 inside so that it can drive LEDs directly.
 
\end_layout

\begin_layout Paragraph*
Square Wave SQ2: 
\end_layout

\begin_layout Standard
Output swings from 0 to 5 volts and frequency can be varied 4Hz to 100kHz.
 All intermediate values of frequency are not possible.
 The duty cycle of the output is programmable.
 SQR2 is not available when WG is active.
\end_layout

\begin_layout Paragraph*
Digital Output (OD1) :
\end_layout

\begin_layout Standard
The voltage at OD1 can be set to 0 or 5 volts, using software.
\end_layout

\begin_layout Paragraph*
Sine/Triangular Wave WG: 
\end_layout

\begin_layout Standard
Frequency can be varied from 5Hz to 5kHz.
 The peak value of the amplitude can be set to 3 volts, 1.0 volt or 80 mV.
 Shape of the output waveform is programmable.
 Using the GUI sine or triangular can be selected.
 WG bar is inverted WG.
\end_layout

\begin_layout Subsubsection*
Inputs:
\end_layout

\begin_layout Paragraph*
Capacitance meter IN1:
\end_layout

\begin_layout Standard
Capacitance connected between IN1 and Ground can be measured.
 It works better for lower capacitance values, upto 10 nanoFarads, results
 may not be very accurate beyond that.
 
\end_layout

\begin_layout Paragraph*
Frequency Counter IN2:
\end_layout

\begin_layout Standard
Capable of measuring frequencies upto several MHz.
 
\end_layout

\begin_layout Paragraph*
Resistive Sensor Input (SEN):
\end_layout

\begin_layout Standard
This is mainly meant for sensors like Light Dependent Resistor, Thermistor,
 Photo-transistor etc.
 SEN is internally connected to 3.3 volts through a 
\begin_inset Formula $5.1k\Omega$
\end_inset

 resistor.
\end_layout

\begin_layout Paragraph*
\begin_inset Formula $\pm16V$
\end_inset

 Analog Inputs, A1 & A2: 
\end_layout

\begin_layout Standard
Can measure voltage within the 
\begin_inset Formula $\pm16$
\end_inset

 volts range.
 The input voltage range can be selected from .5V to 16V fullscale.
 Voltage at these terminals can be displayed as a function of time, giving
 the functionality of a low frequency oscilloscope.
 The maximum sampling rate is 1 Msps /channel.
 Both have an input impedance of 
\begin_inset Formula $1M\Omega$
\end_inset

 .
\end_layout

\begin_layout Paragraph*
\begin_inset Formula $\pm3.3V$
\end_inset

 Analog Input A3: 
\end_layout

\begin_layout Standard
Can measure voltage within the 
\begin_inset Formula $\pm3.3$
\end_inset

 volts range.
 The input can be amplified by connecting a resistor from Rg to Ground,
 gain =
\begin_inset Formula $1+\frac{Rg}{10000}$
\end_inset

.
 This enables displaying very small amplitude signals.
 The input impedance of A3 is 
\begin_inset Formula $10M\Omega$
\end_inset

.
\end_layout

\begin_layout Paragraph*
Microphone input MIC:
\end_layout

\begin_layout Standard
A condenser microphone can be connected to this terminal and the output
 can be captured.
\end_layout

\begin_layout Subsubsection*
I2C Sensor Interface: 
\end_layout

\begin_layout Standard
The four connections (+5V, Ground, SCL and SDA) of the 8 terminal berg strip
 supports I2C sensors.
 The software is capable of recognizing a large number of commercially available
 I2C sensors.
\end_layout

\begin_layout Subsubsection*
\begin_inset Formula $\pm6V/10mA$
\end_inset

 Power supply: 
\end_layout

\begin_layout Standard
The VR+ and VR- are regulated power outputs.
 They can supply very little current, but good enough to power an Op-Amp.
\end_layout

\begin_layout Subsection
Accessory Set
\end_layout

\begin_layout Standard
Some accessories are provided with expEYES.
\end_layout

\begin_layout Itemize
Pieces of wires, with pin and with crocodile clip.
\end_layout

\begin_layout Itemize
Condenser microphone with leads.
\end_layout

\begin_layout Itemize
Inductor Coil (2) : 44SWG wire on 1cm dia bobbin.
 Around 3000 Turns (some may have more turns).
 These coils can be used for studying inductance, electromagnetic induction
 etc.
 
\end_layout

\begin_layout Itemize
Piezo Electric Discs (2) : Resonant frequency is around 3500 Hz.
 Can be energized by WG output or SQR1.
 Discs are enclosed in a plastic shell that forms a cavity, that enhances
 the amplitude of sound produced.
\end_layout

\begin_layout Itemize
DC Motor : Should be powered by a DC voltage less than 3 volts.
\end_layout

\begin_layout Itemize
Permanent Magnets : (a) 10mm dia & length (b) 5 mm dia & 10 mm length (c)
 Button size magnets(2)
\end_layout

\begin_layout Itemize
5mm LEDS : RED, BLUE, GREEN, WHITE
\end_layout

\begin_layout Itemize
Capacitors : 100pF, 0.1uF , 1 uF & 22uF
\end_layout

\begin_layout Itemize
Inductor : 10 mH / 20
\begin_inset Formula $\Omega$
\end_inset

,
\end_layout

\begin_layout Itemize
Resistors : 560
\begin_inset Formula $\Omega$
\end_inset

, 1
\begin_inset Formula $k\Omega$
\end_inset

, 2.2
\begin_inset Formula $k\Omega$
\end_inset

 , 10
\begin_inset Formula $k\Omega$
\end_inset

 , 51
\begin_inset Formula $k\Omega$
\end_inset

 and 100 
\begin_inset Formula $k\Omega$
\end_inset


\end_layout

\begin_layout Itemize
LDR 
\end_layout

\begin_layout Itemize
Two silicon diodes (1N4148) and one 3.3 volts zener diode
\end_layout

\begin_layout Itemize
NPN Transistor( 2N2222)
\end_layout

\begin_layout Section
Software Installation
\end_layout

\begin_layout Standard
ExpEYES can run on any computer having a Python Interpreter and required
 modules.
 The USB interface is handled by a device driver program that presents the
 USB port as a Serial port to the Python programs.
 The communication the expEYES is done using a library written in Python.
 Programs with GUI have been written for many experiments.
 Eyes17 software require the following packages
\end_layout

\begin_layout Itemize
python-serial
\end_layout

\begin_layout Itemize
python-numpy
\end_layout

\begin_layout Itemize
python-scipy
\end_layout

\begin_layout Itemize
python-qt4
\end_layout

\begin_layout Itemize
python-pyqtgraph
\end_layout

\begin_layout Subsubsection*
Any GNU/Linux distributions
\end_layout

\begin_layout Standard
Download 
\series bold
eyes17-x.x.x.zip
\series default
 (the latest version) from 
\series bold
http://expeyes.in
\series default
 and upzip it, and change to the newly created folder.
 Issue the command
\end_layout

\begin_layout LyX-Code
$ sudo sh postinst       # set user write permission
\end_layout

\begin_layout LyX-Code
$ python main.py
\end_layout

\begin_layout Standard
You will get error messages for any missing packages that are required for
 expeyes.
 Install them one by one and try again.
 Python programs required for several experiments are in the same directory,
 they are called by 'main.py'.
\end_layout

\begin_layout Subsubsection*
Debian or Ubuntu GNU/Linux distributions
\end_layout

\begin_layout Standard
Download 
\series bold
eyes17-x.x.x.deb
\series default
 ( the latest version) from the software section of 
\series bold
http://expeyes.in
\series default
 and install it using the command;
\end_layout

\begin_layout Standard
$ sudo gdebi eyes17-x.x.x.deb 
\end_layout

\begin_layout Standard
while connected to Internet
\end_layout

\begin_layout Standard
The package 'eyes17' (later than version 3) does not depend on the earlier
 versions of ExpEYES, like expeyes junior.
 During installation gdebi will automatically dowload and install all the
 required packages.
\end_layout

\begin_layout Subsubsection*
The expEYES Live CD / USB pendrive
\end_layout

\begin_layout Standard
The ISO image containing support for eyes17 can be downloaded from HERE.
 Make a DVD or USB memory stick bootable using this ISO image (Download
 rufus from https://rufus.akeo.ie to do this under MSWindows) 
\end_layout

\begin_layout Standard
Switch off the PC and insert the liveCD/Pendrive and switch it on.
 Enter the BIOS while booting, make the CDdrive/USB hard disk as the first
 boot device.
 A desktop will appear and you can start expEYES-17 from the menu 
\series bold
Applications->Education
\series default
->ExpEYES-17.
 You can also start it from a Terminal using the command:
\end_layout

\begin_layout LyX-Code
$ python /usr/share/expeyes/eyes17/main.py
\end_layout

\begin_layout Subsubsection*
On MSWindows
\end_layout

\begin_layout Standard
The first thing to do is to install the driver software for the USB to serial
 converter IC MCP2200, available on Microchip website (also given on expeyes
 website).
 After installing this the device will appear as a COM port, that can be
 verified from the device manager of MSWindows.
 After this there are two options.
\end_layout

\begin_layout Standard
A zip file containing all the necessary things for ExpEYES is available
 on the website, named eyes17win.zip.
 Unzip this file and run main.py from that.
 By using this method you will not able to write your own Python code to
 access expeyes, for that you need to install the following
\end_layout

\begin_layout Enumerate
Python-2.x version
\end_layout

\begin_layout Enumerate
python-serial
\end_layout

\begin_layout Enumerate
python-qt4
\end_layout

\begin_layout Enumerate
python-pyqtgraph, 
\end_layout

\begin_layout Enumerate
python-numpy
\end_layout

\begin_layout Enumerate
python-scipy
\end_layout

\begin_layout Standard
Download the eyes17-x.x.x.zip ( take latest version) from the website.
 Unzipping the files will create a directory 
\series bold
named eyes17
\series default
, run 
\series bold
main.py
\series default
 from that.
\end_layout

\begin_layout Section
The main GUI program
\end_layout

\begin_layout Standard
Start Applications->Education->ExpEYES-17 from the menu.
 A four channel oscilloscope screen with several extra features will open
 as shown in figure 
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:The-scope17-screen"

\end_inset

.
 Various experiments can be selected from the menu.
\end_layout

\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open

\begin_layout Plain Layout
\align center
\begin_inset Graphics
	filename pics/scope17.png
	lyxscale 60
	width 11cm

\end_inset


\end_layout

\begin_layout Plain Layout
\begin_inset Caption Standard

\begin_layout Plain Layout
The scope17 screen showing two traces
\begin_inset CommandInset label
LatexCommand label
name "fig:The-scope17-screen"

\end_inset


\end_layout

\end_inset


\end_layout

\end_inset


\end_layout

\begin_layout Standard
The main window looks like a low frequency four channel oscilloscope, with
 some extra features, on the right side panel.
 Applications for various experiments can be selected from the pulldown
 menu.
 A brief description of the oscilloscope program is given below.
\end_layout

\begin_layout Itemize
Any of the four inputs (A1, A2, A3 or MIC) can be enabled using the correspondin
g checkbox.
 The input range can be selected by clicking on the menubutton on the right
 side of the checkbox.
 Select the desired input range from the popup menu.
\end_layout

\begin_layout Itemize
There is another checkbox, to enable mathematical fitting of the data using
 
\begin_inset Formula $V=V_{0}\sin\left(2\pi ft+\theta\right)+C$
\end_inset

 to show the amplitude and frequency.
\end_layout

\begin_layout Itemize
The horizontal scale (time base) can be changed by a slider, from .5 mS fullscale
 to 500 mS full scale.
\end_layout

\begin_layout Itemize
The Checkbutton 
\series bold
Freeze
\series default
, allows to pause and resume the oscilloscope operation.
\end_layout

\begin_layout Itemize
The Trigger level can be set by a slider, and there is a menubutton to select
 the trigger source.
\end_layout

\begin_layout Itemize
To save the traces to a file, edit the filename and click on the 
\series bold
SaveTo
\series default
 button.
\end_layout

\begin_layout Itemize
Clicking on 
\series bold
FFT
\series default
 shows the frequency spectrum of all the eneabled channels, appears on popup
 windows.
\end_layout

\begin_layout Standard
In addition to the Oscilloscope, there are several measurement/control options
 available on the GUI, they are explained below.
\end_layout

\begin_layout Itemize
If selected, the voltages at the inputs A1, A2 and A3 are sampled every
 second and displayed.
\end_layout

\begin_layout Itemize
The resistance connected between SEN and Ground is measured and displayed
 every second.
\end_layout

\begin_layout Itemize
Clicking 
\series bold
Capacitance on IN1
\series default
, measures the value of the capacitor connected between IN1 and GND.
\end_layout

\begin_layout Itemize
Clicking 
\series bold
Frequency on IN2
\series default
, measures the frequency of an external digital (TTL standard) pulse connected
 to IN2
\end_layout

\begin_layout Itemize
The shape of the waveform can be selected using the menubutton, default
 shape is sine.
 It can be changed to triangular.
 When the square wave option is selected, the output is shifted to SQ2.
 You cannot have sine/triangular and SQ2 at the same time.
\end_layout

\begin_layout Itemize
Frequency of the Waveform generator WG can be set using the slider or the
 text entry window.
 The two input methods follow each other, changing the slider will change
 the text field and entering data using text field will set the slider to
 that value.
 The frequency will be set to the nearest possible value and it will be
 displayed in the message window at the bottom.
 The amplitude of WG output can be set to 3 volts, 1 volt or 80 mV.
\end_layout

\begin_layout Itemize
SQ1 can be set using the same method as explained above.
 The duty cycle can be set between 1% to 99%, default is 50%.
\end_layout

\begin_layout Itemize
The programmable volages PV1 and PV2 are also set in a similar manner.
\end_layout

\begin_layout Itemize
Checkbuttons are provided to control OD1 and CCS.
\end_layout

\begin_layout Section
Getting Familiar with ExpEYES17
\end_layout

\begin_layout Standard
Before proceeding with the experiments, let us do some simple exercises
 to become familiar with expEYES-17.
 Connect the device a USB port and start the ExpEYES-17 program from the
 menu 'Applications->Education'.
 Enable the 'Popup Help' option and select the first few items from the
 school menu.
\end_layout

\begin_layout Standard
The following chapters are organized according to the pulldown menus of
 the eyes17 program, each chapter containing the experiments under the correspon
ding menu; like School level, Eelectronics, Eelectrical etc.
 To perform the expeiment, select it from the menu.
 Online help is available for every experiment, making this manual almost
 redundant.
\end_layout

\begin_layout Standard
The screen shots given in this document are not from the GUI program, because
 the black background images are difficult to print.
 The plots are generated by separate code.
\end_layout

\begin_layout Chapter
School Level Experiments
\end_layout

\begin_layout Standard
This chapter will discuss the experiments and demonstrations without much
 data analysis, experiments given in the menu SchoolExpts.
 Simple tasks like measuring voltage, resistance, capacitance etc.
 will be done followed by resistances changing with temperature or light.
 The concept of Alternating Current is introduced by plotting the voltage
 as a function of time.
 Generating and digitizing sound will be covered.
 When an experiment is selected, the corresponding help window will popup,
 if enabled.
\end_layout

\begin_layout Section
Measuring Voltage
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn to measure voltage using expEYES and get some idea about the concept
 of Electrical Ground.
 A dry-cell and two wires are required.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/measure-dc.svg
	height 1cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Observe the voltage at A1 displayed.
\end_layout

\begin_layout Itemize
Repeat by reversing the cell connections.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Voltages measured value is +1.5 volts and it becomes -1.5 after reversing
 the connections.
\end_layout

\begin_layout Standard
We are measuring the potential difference between two points.
 One of them can be treated as at zero volts, or Ground potential.
 The voltage measuring points of expEYES measure the voltage with respect
 to the terminals marked GND.
 We have connected the negative terminal of the cell to Ground.
 The positive terminal is at +1.5 volts with respect to the negative terminal.
 
\shape italic
Will it show correct voltage if GND is not connected ?
\end_layout

\begin_layout Section
Measuring Resistance
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
ExpEYES has a terminal marked 
\series bold
SEN
\series default
, that can be used for measuring resistances in the range of 100
\begin_inset Formula $\Omega$
\end_inset

 to 100 
\begin_inset Formula $k\Omega$
\end_inset

.
 You can also study the series and parallel combination of resistors.
 Effective resistance of a series combination of resistors, 
\begin_inset Formula $R=R1+R2+\cdots$
\end_inset

 .
 For parallel combination it is given by 
\begin_inset Formula $\frac{1}{R}=\frac{1}{R1}+\frac{1}{R2}+\cdots$
\end_inset


\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/res-measure.svg
	height 2cm

\end_inset


\begin_inset Graphics
	filename schematics/res-series.svg
	height 2cm

\end_inset


\begin_inset Graphics
	filename schematics/res-parallel.svg
	height 2cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Connect the resistor between SEN and any Ground terminal
\end_layout

\begin_layout Itemize
Observe the value shown on the right side panel
\end_layout

\begin_layout Itemize
Try series and parallel combinations
\end_layout

\begin_layout Section
Measuring Capacitance
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measuring capacitance and explore the series and parallel combinations of
 capacitors.
\end_layout

\begin_layout Paragraph*
\begin_inset Graphics
	filename schematics/cap-measure.svg
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename schematics/cap-series.svg
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename schematics/cap-parallel.svg
	height 2cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Connect the capacitor between IN1 and Ground.
\end_layout

\begin_layout Itemize
Click on 
\begin_inset Quotes eld
\end_inset

Capacitance on IN1
\begin_inset Quotes erd
\end_inset

 .
 Should not touch the capacitor while measuring
\end_layout

\begin_layout Itemize
Repeat the measurement for Series and parallel combinations
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
We have used 100pF capacitors in this activity.
 For parallel combination, the effective capacitance is given by 
\begin_inset Formula $C=C1+C2+\cdots$
\end_inset

 , and for series combination by 
\begin_inset Formula $\frac{1}{C}=\frac{1}{C1}+\frac{1}{C2}+\cdots$
\end_inset

 .
 You can make the capacitors by pasting thin metal foils on both sides of
 insulators like paper, polythene or glass.
\end_layout

\begin_layout Section
Measure resistance by comparison
\begin_inset CommandInset label
LatexCommand label
name "sec:Measure-resistance-by-comparison"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn to apply Ohm's law to find the value of an unknown resistance by comparing
 it with a known one.
 Voltage across a resistor is given by 
\begin_inset Formula $V=IR$
\end_inset

 .
 If same amount of current is flowing through two different resistors, the
 ratio of voltages will be the same as the ratio of resistances, 
\begin_inset Formula $I=\frac{V_{A1}}{R2}=\frac{V_{PV1}-V_{A1}}{R1}$
\end_inset

.
\end_layout

\begin_layout Paragraph*
\begin_inset Graphics
	filename schematics/res-compare.svg
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Connect the unknown resistor R from PV1 to A1.
\end_layout

\begin_layout Itemize
Connect 1
\begin_inset Formula $k\Omega$
\end_inset

 (R2) from A1 to Ground.
\end_layout

\begin_layout Itemize
Set PV1 to 4 volts.
\end_layout

\begin_layout Itemize
Measure voltage at A1.
 Calculate the current 
\begin_inset Formula $I=\frac{V_{A1}}{R2}$
\end_inset

 .
 Value of 
\begin_inset Formula $R1=\frac{V_{PV1}-V_{A1}}{I}$
\end_inset

.
\end_layout

\begin_layout Itemize
Select Electrical->Plot I-V curve from the menu to get an I-V plot
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
What is the limitation of this method ? How do we choose the reference resistor
 ? suppose the unknown value is in Mega Ohms, what will be the voltage drop
 across a 
\begin_inset Formula $1k\Omega$
\end_inset

 reference resistor ? Our voltage measurement is having a resolution of
 
\begin_inset Formula $\frac{1}{4095}$
\end_inset

.
\end_layout

\begin_layout Standard
We will use this method later to measure the resistance of solutions, using
 AC.
\end_layout

\begin_layout Section
Direct and Alternating Currents
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Introduce the concept of time dependent voltages, using a V(t) graph.
 Compare the graph of DC and AC.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/ac-dc.svg
	height 1cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Set PV1 to 2 volts and Set WG to 200 Hz
\end_layout

\begin_layout Itemize
Enable analyse on A1, to measure amplitude and frequency.
\end_layout

\begin_layout Itemize
Enable A2
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
In the plot if voltage is not changing, it is pure DC.
 If the voltage is changing with time, it has an AC component.
 if the average voltage is zero, it is pure DC.
 In the second plot, the voltage is changing from zero to file volts, is
 it AC, DC or something else ???
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/ac-dc.png
	lyxscale 70
	height 5cm

\end_inset

 
\begin_inset Graphics
	filename pics/sqr-wave.png
	lyxscale 70
	height 5cm

\end_inset


\end_layout

\begin_layout Section
AC mains pickup
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn about the AC mains supply.
 Explore the phenomenon of propagation of AC through free space.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/line-pickup.svg
	lyxscale 70
	height 1.5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Connect a long wire to A3
\end_layout

\begin_layout Itemize
Take one end of the wire near the AC mains line, without touching any mains
 supply.
\end_layout

\begin_layout Itemize
Enable A3, and it's analysis.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The power line pickup is shown below, there are five cycles in 100 milliseconds.
 Without making any connection, how are we getting the AC voltage from the
 mains supply ? Why the voltage increaes when you touch the end of the wire
 connected to A1 by hand.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/pickup.png
	lyxscale 70
	height 5cm

\end_inset


\end_layout

\begin_layout Section
Separating DC & AC components
\begin_inset CommandInset label
LatexCommand label
name "sec:DC-&-AC"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Separating AC and DC components of a voltage waveform using a capacitor.
\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/acdc-separating.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/acdc-sep-screen.png
	lyxscale 50
	height 5cm

\end_inset


\end_layout

\begin_layout Itemize
Set SQR1 to 500 Hz
\end_layout

\begin_layout Itemize
Enable A1 and A2
\end_layout

\begin_layout Itemize
Adjust the horizontal scale to see several cycles.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The observed waveforms with and without the series capacitor are shown in
 figure.
 The voltage is swinging between 0 and 5 volts.
 After passing through the capacitor the voltage swings from -2.5 volts to
 +2.5 volts.
\end_layout

\begin_layout Standard
What will you get if you subtract a 2.5 from the y-coordinate of every point
 of the first graph? That is what the capacitor did.
 It did not allow the DC part to pass through.
 This original square wave can be considered as a 2.5V AC superimposed on
 a 2.5V DC.
\end_layout

\begin_layout Standard
You may need to connect a resistor from A2 to GND to see a waveform swinging
 between -2.5 to +2.5 volts.
 Remove the resistor and observe the result.
 
\end_layout

\begin_layout Section
Human body as a conductor
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Touching the AC mains is fatal to us because our body is a conductor.
 We can explore this using low voltage signals.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/conducting-human.svg
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename pics/conducting-human-screen.png
	lyxscale 50
	height 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Set WG to 200 Hz.
\end_layout

\begin_layout Itemize
Enable A1, A2 with analysis enabled.
\end_layout

\begin_layout Itemize
Conenct WG and A1, with a wire
\end_layout

\begin_layout Itemize
Connect WG and A2 through your body and note voltages
\end_layout

\begin_layout Itemize
Repeat it using a 3 volt DC signal from PV1.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The observed peak voltage will be less than 3volts, due to the resistance
 of the body.
 There could be some ripple due to the 50Hz AC pickup.
 This can be eliminated by performing the experiment far away from power
 lines, using a laptop.
\end_layout

\begin_layout Section
Resistance of human body
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measure the resistance of human body by comparing it with a known resistor.
 We start with a DC input from PV1 and then using the AC signal from WG.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/res-body.svg
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Set PV1 to 3 volts
\end_layout

\begin_layout Itemize
Join PV1 and A2, through your body and measure voltage at A2
\end_layout

\begin_layout Itemize
Calculate your body's resistance, as given in section 
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Measure-resistance-by-comparison"

\end_inset


\end_layout

\begin_layout Itemize
Repeat using SINE instead of PV1.
 Enable analysis on A1 and A2 to measure voltage.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The DC measurements are affected more by the electrical noise.
 The AC resistance should be less than the DC resistance.
 The resistance is due to our skin and AC can pass through this, like it
 passes through a capacitor.
\end_layout

\begin_layout Section
Light dependent resistors
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn about LDR.
 Measure intensity of light and its variation with distance from the source.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/ldr.svg
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Measure the LDR's resistance, for different light intensities.
\end_layout

\begin_layout Itemize
Iluminate LDR using a fluorescent lamp, A1 should show ripples
\end_layout

\begin_layout Itemize
Put A1 in AC mode and measure ripple frequency
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The resistance vary from 1k
\begin_inset Formula $\Omega$
\end_inset

 to around 100 k
\begin_inset Formula $\Omega$
\end_inset

 depending on the intensity of light falling on it.
 The voltage is proportional to the resistance.
 The resistance decreases with intensity of light.
 If you use a point source of light, the resistance should increase as the
 square of the distance between the LDR and the light source.
\end_layout

\begin_layout Section
Voltage of a lemon cell 
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Make a voltage source by inserting Zinc and Copper plates into a lemon.
 Explore the current driving capability and internal resistance.
\end_layout

\begin_layout Paragraph*
\begin_inset Graphics
	filename schematics/lemon-cell.svg
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Click on A1 to measure voltage
\end_layout

\begin_layout Itemize
Measure the voltage with and without the 1k resistor
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Voltage across the Copper and Zinc terminals is nearly .9 volts.
 Connecting the resistor reduces it to 0.33 volts.
 When connected, current will start flowing through the resistor.
 But why is the voltage going down ?
\end_layout

\begin_layout Standard
What is the internal resistance of the cell ?
\end_layout

\begin_layout Standard
Current is the flow of charges and it has to complete the path.
 That means, current has to flow through the cell also.
 Depending on the internal resistance of the cell, part of the voltage gets
 dropped inside the cell itself.
 Does the same happen with a new dry-cell ?
\end_layout

\begin_layout Section
A simple AC generator
\begin_inset CommandInset label
LatexCommand label
name "sec:A-simple-AC"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measure the frequency and amplitude of the voltage induced across a solenoid
 coil by a rotating magnet.
 Use the 10 mm x 10 mm magnet and the 3000T coils that comes with the kit.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/ac-generator.svg
	lyxscale 60
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/ac-gen-screen.png
	lyxscale 60
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Mount the magnet horizontally and power the DC motor from a 1.5 volts cell
\end_layout

\begin_layout Itemize
Enable A1 and A2, with analysis option
\end_layout

\begin_layout Itemize
Set timebase to 100 mS full scale
\end_layout

\begin_layout Itemize
Bring the coil near the magnet (not to touch it), watch the induced voltage
\end_layout

\begin_layout Itemize
Repeat the experiment using 2 coils.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The voltage output is shown in figure.
 The phase difference between the two voltages depends on the angle between
 the axes of the two coils.
\end_layout

\begin_layout Standard
Bring a shorted coil near the magnet to observe the change in frequency.
 The shorted coil is drawing energy from the generator and the speed get
 reduced.
 The magnetic field in this generator is very weak.
 The resistance of the coil is very high and trying to draw any current
 from it will drop most of the voltage across the coil itself.
 
\end_layout

\begin_layout Section
AC Transformer
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Demonstrate mutual induction using two coils, supplied with ExpEYES.
 One coil, the primary, is connected between WG and Ground.
 The axes of the coils are aligned and a ferrite core is inserted.
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align left
\begin_inset Graphics
	filename schematics/transformer.svg
	height 4cm

\end_inset

 
\begin_inset Graphics
	filename pics/transformer-screen.png
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Make connections as shown in the figure
\end_layout

\begin_layout Itemize
Enable A1 and A2
\end_layout

\begin_layout Itemize
Set WG to 500 Hz
\end_layout

\begin_layout Itemize
Bring the coils close and watch the voltage on A2.
\end_layout

\begin_layout Itemize
Try inserting an ion core
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The applied waveform and the induced waveform are shown in figure.
 A changing magnetic filed is causing the induced voltage.
 In the previous two experiments, the changing magnetic field was created
 by the movement of permanent magnets.
 In the present case the changing magnetic field is created by a time varying
 current.
\end_layout

\begin_layout Standard
Try doing this experiment using a squarewave.
 Connect a 1k
\begin_inset Formula $\Omega$
\end_inset

 resistor across secondary coil to reduce ringing.
\end_layout

\begin_layout Standard
The concept of Alternating Current is introduced by plotting the voltage
 as a function of time.
 The behavior of circuits elements like capacitors and inductors in AC and
 DC circuits are explored, by measuring parameters like amplitude, frequency
 and phase.
 Converting electrical signals into sound and back is demonstrated.
 
\end_layout

\begin_layout Standard
For each experiment, make connections as per the diagram given.
\end_layout

\begin_layout Section
Resistance of water, using AC
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measure the resistance of ionic solutions, using both DC and AC voltages.
 We have used normal tap water.
 Try measuring the resistance using a multimeter first.
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align center
\begin_inset Graphics
	filename schematics/res-water.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/water-conduct.png
	lyxscale 50
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
R1 should be comparable to R, start with 10k.
\end_layout

\begin_layout Itemize
Enable A1 and A2
\end_layout

\begin_layout Itemize
Calculate the resistance as explained in section 
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Measure-resistance-by-comparison"

\end_inset


\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Observed values are shown in the table.
 The DC and AC resistances seems to be very different.
 With DC, the resistance of the liquid changes with time, due to electrolysis
 and bubble formation.
 The resistance does not depend much on the distance between the electrodes,
 the area of the electrode is having some effect.
 The resistance depends on the ion concentration and presence of impurities
 in the water used.
\end_layout

\begin_layout Standard
Try changing the distance between electrodes.
 Try adding some common salt and repeat the measurements.
 Why is the behavior different for AC and DC ? What are the charge carriers
 responsible for the flow of electricity through solutions ? Is there any
 chemical reaction taking place ?
\end_layout

\begin_layout Section
Generating sound
\begin_inset CommandInset label
LatexCommand label
name "sec:Generating Sound "

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Generate sound from electrical signals, using a Piezo-electric buzzer.
 Digitize sound and measure its frequency.
 Use the Piezo buzzer or any other source of sound like a tuning fork.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/sound-generator.svg
	height 3cm

\end_inset


\end_layout

\begin_layout Itemize
Enable A1, and its analysis
\end_layout

\begin_layout Itemize
Set WG to 1000Hz, change it and listen to the sound.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
When you change the frequency of the voltage that excites the Piezo, both
 the frequency and the intesity of the sound changes.
 The intensity is maximum near 3500 Hz, due to resonance.
 The resonant frequency of the Piezo buzzer is decided by its size and mechanica
l properties.
\end_layout

\begin_layout Section
Digtizing sound
\begin_inset CommandInset label
LatexCommand label
name "sec:Digtizing-sound"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Digitize sound signals from a microphone, and measure its frequency.
 Use the Piezo buzzer or any other source of sound like a tuning fork.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/sound-capture.svg
	height 3cm

\end_inset


\end_layout

\begin_layout Itemize
Enable A1 and MIC , with analysis
\end_layout

\begin_layout Itemize
Position the buzzer facing the microphone
\end_layout

\begin_layout Itemize
Set WG to 1000Hz, change it and watch the MIC output
\end_layout

\begin_layout Itemize
Use a whistle instead of the buzzer and find out the frequency of MIC output.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The driving signal and the microphone output is shown in figure
\end_layout

\begin_layout Standard
Sound waves create pressure variations in the medium through which it travel.
 The microphone generates a voltage proportional to the pressure.
 The voltage variations are in tune with the pressure variations.
 You can consider the microphone as a pressure sensor, but working only
 for time varying pressures.
 
\end_layout

\begin_layout Chapter
Electronics
\end_layout

\begin_layout Standard
This chapter explains several electronics experiments.
 Most of them are done using the oscilloscope GUI.
 Some of them like Diode and Transistor characteristics have a dedicated
 GUI.
\end_layout

\begin_layout Section
Half wave rectifier using PN junction
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn the working of a PN junction diode as a rectifier.
 RC filtering to reduce the ripple (the AC component).
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/halfwave.svg
	lyxscale 50
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/halfwave.png
	lyxscale 50
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Connect a 1k load resistor, note the difference in amplitude
\end_layout

\begin_layout Itemize
Connect a 1uF capacitor, and see the filtering effect.
\end_layout

\begin_layout Itemize
Try different values load resistors and filter capacitors
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The negative half is removed by the diode as shown in figure.
 Also notice that the voltage in the positive half is reduced by around
 0.7 volts, the voltage drop across a silicon diode.
 A load resistor is required for the proper operation of the circuit, it
 could be more than 1k
\begin_inset Formula $\Omega$
\end_inset

 but do NOT use very low values since our AC source can drive only up to
 5 mA current.
\end_layout

\begin_layout Standard
We can see that the capacitor charges up and then during the missing cycle
 it maintains the voltage.
 The remaining AC component is called the ripple in the DC.
\end_layout

\begin_layout Standard
Can we use very large capacitance to reduce the ripple ?
\end_layout

\begin_layout Standard
During what part of the cycle does current flow through the diode ?
\end_layout

\begin_layout Standard
Amount of peak current is decided by what ?
\end_layout

\begin_layout Section
Fullwave rectifier using PN junctions
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Make a full wave rectifier, using two diodes.
 Two AC waveforms, differing by 180 degree in phase as required.
 WG and WG bar provide the same.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/fullwave.svg
	height 4cm

\end_inset

 
\begin_inset Graphics
	filename pics/fullwave.png
	lyxscale 60
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Make connections
\end_layout

\begin_layout Itemize
Enable A1, A2 and A3
\end_layout

\begin_layout Itemize
Set WG to 200Hz and adjust timebase to view 4 to 5 cycles
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Adding capacitors to reduce the ripple is left as an exercise to the user.
 This experiment is only to demonstrate the working of a full wave rectifier,
 it cannot provide more than few milli amperes of current.
 
\end_layout

\begin_layout Standard
Why full-wave rectifier is superior to half-wave rectifier ?
\end_layout

\begin_layout Section
Clipping using PN junction diode
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Demostrate clipping of an AC signal at different levels, using a PN junction
 diode
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/clipping.svg
	lyxscale 50
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/clipping.png
	lyxscale 60
	height 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Change PV1 and note the difference in the output
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The clipping level is decided by the applied DC voltage and the diode drop.
\end_layout

\begin_layout Section
Clamping using PN junction diode
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Demostrate clamping of an AC signal at different levels, using a PN junction
 diode
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/clamping.svg
	lyxscale 50
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/clamping.png
	lyxscale 60
	height 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Change PV1 and note the difference in the output
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The clamping level is decided by the applied DC voltage and the diode drop.
\end_layout

\begin_layout Section
IC555 Oscillator
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Wire an astable multivibrator circuit using IC555, measure the frequency
 and duty cycle of the output.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/osc555.svg
	lyxscale 50
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/ic555-screen.png
	lyxscale 50
	height 3cm

\end_inset


\end_layout

\begin_layout Standard
Circuit is shown in figure.
 The frequency is given by 
\begin_inset Formula $f=1/\left(\ln2\times C\times\left(R_{1}+2R_{2}\right)\right)$
\end_inset

.
 The HIGH time is given by 
\begin_inset Formula $\ln2\times C\times\left(R_{1}+R_{2}\right)$
\end_inset

 and LOW time by 
\begin_inset Formula $\ln2\times C\times R_{2}$
\end_inset

.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Make connections
\end_layout

\begin_layout Itemize
measure frequency and duty cycle.
\end_layout

\begin_layout Itemize
Repeat by changing the value of R1
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The output waveform is shown in figure.
 Change the value of resistors or the capacitor, and compare the frequency
 and duty cycle with the calculated values.
\end_layout

\begin_layout Section
Inverting Amplifier
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Wire an Inverting amplifier using an Op-Amp and test it.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/opamp-inv.svg
	lyxscale 50
	height 3cm

\end_inset

 
\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Set WG amplitude to 80 mV and frequency to 1000 Hz
\end_layout

\begin_layout Itemize
Enable A1 and A2 and their analysis option
\end_layout

\begin_layout Itemize
Select 1V range for both A1 and A2 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Change gain by changing the resistor values.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The amplitude gain and and the phase difference can be observed from the
 results.
\end_layout

\begin_layout Section
Non-Inverting Amplifier
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Wire an Inverting amplifier using an Op-Amp and test it.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/opamp-noninv.svg
	lyxscale 50
	height 3cm

\end_inset

 
\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Set WG amplitude to 80 mV and frequency to 1000 Hz
\end_layout

\begin_layout Itemize
Enable A1 and A2 and their analysis option
\end_layout

\begin_layout Itemize
Select 1V range for both A1 and A2 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Change gain by changing the resistor values.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The amplitude gain and and the phase correlation can be observed from the
 results.
\end_layout

\begin_layout Section
Op-Amp Ingrator
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Wire an Inverting amplifier using an Op-Amp and test it.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/opamp-int.svg
	lyxscale 50
	height 3cm

\end_inset

 
\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Set WG amplitude to 80 mV and frequency to 1000 Hz
\end_layout

\begin_layout Itemize
Enable A1 and A2 and their analysis option
\end_layout

\begin_layout Itemize
Select 1V range for both A1 and A2 
\end_layout

\begin_layout Itemize
Make connections and observe the output
\end_layout

\begin_layout Itemize
Change gain by changing the resistor values.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The amplitude gain and and the phase correlation can be observed from the
 results.
\end_layout

\begin_layout Section
Logic gates
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Study of logic gates using SQ1 and PV1 as inputs, using TTL logic ICs 7408
 and 7432.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/logic-gates.svg
	height 3cm

\end_inset

 
\end_layout

\begin_layout Itemize
Enable A1, A2 ands A3.
 Set input range on A1 and A2 to 8V
\end_layout

\begin_layout Itemize
Set SQ1 to 200 Hz and adjust timebase to view several cycles
\end_layout

\begin_layout Itemize
Select SQ2 from the WG wave shape, set WG to 200 Hz
\end_layout

\begin_layout Itemize
Repeat using the OR gate, 7432
\end_layout

\begin_layout Itemize
The 1k resistor is required to give the 5 volt signal to A3 input
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The working of the logic gate will be evident from the 3 waveforms.
 You may shift traces vertically to separate them for clarity.
\end_layout

\begin_layout Section
Clock Divider
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Study of a clock divider, using a D flip-flop (TTL family, 7474).
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/clock-divider.svg
	height 4cm

\end_inset


\end_layout

\begin_layout Itemize
Enable A1 and A2, set range to 8 volts fullscale
\end_layout

\begin_layout Itemize
Set SQ1 to 500 Hz
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The output toggles at every rising edge of the input, resulting in a division
 of frequency by two.
 The output is a symmetric squarewave, irrespective of the duty cycle of
 the input pulse.
 The HIGH output of the TTL IC is around 4 volts only.
\end_layout

\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open

\begin_layout Plain Layout
\align center
\begin_inset Graphics
	filename pics/clock-divider.png
	lyxscale 50
	width 5cm

\end_inset

 
\begin_inset Graphics
	filename pics/clock-divider2.png
	lyxscale 50
	width 5cm

\end_inset


\end_layout

\begin_layout Plain Layout
\begin_inset Caption Standard

\begin_layout Plain Layout
A clock divider circuit, using a D-flipflop.
 Outputs for two different types of input are shown
\begin_inset CommandInset label
LatexCommand label
name "fig:A-clock-divider-1"

\end_inset

 
\end_layout

\end_inset


\end_layout

\end_inset


\end_layout

\begin_layout Section
Diode I-V characteristics
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Draw the I-V Characteristic of diode and compare the result with the theory.
 
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\align left
\begin_inset Graphics
	filename schematics/diode_iv.svg
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename pics/diode-iv-screen.png
	lyxscale 50
	height 4cm

\end_inset


\end_layout

\begin_layout Itemize
Make connections
\end_layout

\begin_layout Itemize
Click on START to draw the characteristic curve.
\end_layout

\begin_layout Itemize
Analyse the data
\end_layout

\begin_layout Itemize
Plot the IV of LEDs
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The IV characteristic of an ideal PN junction diode is given by equation
 
\begin_inset Formula $I=I_{0}\left(e^{\frac{qV}{kT}}-1\right)$
\end_inset

, where 
\begin_inset Formula $I_{0}$
\end_inset

 is the reverse saturation current, 
\begin_inset Formula $q$
\end_inset

 the charge of electron, 
\begin_inset Formula $k$
\end_inset

 the Boltzmann constant, 
\begin_inset Formula $T$
\end_inset

 the temperature in Kelvin.
 For a practical, non-ideal, diode, the equation is 
\begin_inset Formula $I=I_{0}\left(e^{\frac{qV}{nkT}}-1\right)$
\end_inset

, where 
\begin_inset Formula $n$
\end_inset

 is the ideality factor, that is 
\begin_inset Formula $1$
\end_inset

 for an ideal diode.
 For practical diodes it varies from 1 to 2.
 We have used a IN4148 silicon diode.
 The value of n for 1N4148 is around 2.
 We have calculated the value of 
\begin_inset Formula $n$
\end_inset

 by fitting the experimental data with the equation.
 
\end_layout

\begin_layout Standard
The voltage at which LED starts emitting light depends on its wavelength
 and Planck's constant.
 Energy of a photon is given by 
\begin_inset Formula $E=h\nu=hc/\lambda$
\end_inset

 .
 This energy is equal to the energy of an electron that overcomes the junction
 barrier and is given by 
\begin_inset Formula $E=eV_{0}$
\end_inset

.
 So Planck's constant 
\begin_inset Formula $h=eV_{0}\lambda/c$
\end_inset

 , where 
\begin_inset Formula $\lambda$
\end_inset

 is the wavelength of light from the LED, 
\begin_inset Formula $e$
\end_inset

 the charge of electron and 
\begin_inset Formula $c$
\end_inset

 the velocity of light.
 
\end_layout

\begin_layout Standard
Repeat the experiment by heating the diode to different temperatures.
\end_layout

\begin_layout Section
Transistor Output characteristics (CE)
\begin_inset CommandInset label
LatexCommand label
name "sec:Transistor-CE-Characteristic"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Plot the output characteristic curve of a transistor.
 Collector is connected to PV1 through a 1K resistor.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/transistor_out.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/transistor-ce.png
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Set base voltage to the 1 volt and START.
 
\end_layout

\begin_layout Itemize
Repeat for different base currents.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The characteristic curves for different base currents are shown in figure.
 The collector current is obtained from the voltage difference across the
 1k resistor.
 
\end_layout

\begin_layout Standard
The base current is set by setting the voltage at one end of the 100 k
\begin_inset Formula $\Omega$
\end_inset

 resistor, the other end is connected to the transistor base.
 The value of base current is calculated by, 
\begin_inset Formula $I_{b}=\frac{V_{pv2}-V_{A2}}{100\times10^{3}}\times10^{6}\mu A$
\end_inset

.
 If A2 is not connected, the code assumes 0.6 volts at the base to calculate
 the base current.
 
\end_layout

\begin_layout Section
Opto-electric signal transmission 
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Demonstrate the transmission of signals using light.
 An LED is powered by a 1kHz signal and the light is made to fall on a photo-tra
nsistor.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/opto-electric.svg
	lyxscale 60
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/opto-electric-transmission.png
	lyxscale 70
	height 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Keep the LED facing the photo-transistor and set SQR1 to 1000Hz
\end_layout

\begin_layout Itemize
Repeat the experiment by changing the frequency.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The SEN input is internally connected to 5 volts through a 5.1k resistor.
 The output of the photo-transistor at 1kHz is shown in figure.
 The square trace is the voltage across the LED.
 When the LED is ON, photo-transistor conducts and the voltage across the
 collector drops to .2 volts.
 When the LED is OFF the photo-transistor goes into cut off mode and the
 collector shows almost the supply voltage.
 The rise and fall times of the photo-transistor seem to be different.
 Find the upper limit of the frequency that the given photo-transistor can
 respond.
\end_layout

\begin_layout Standard
Repeat this experiment with a Fiber Optic cable to guide the light from
 LED to the photo-transistor.
\end_layout

\begin_layout Chapter
Electricity and Magnetism
\end_layout

\begin_layout Standard
This section mainly contains experiments on the steady state and transient
 response of LCR circuit elements.
 the experimental results with the theory.
 It also gives an experiment of electromagnetic induction.
\end_layout

\begin_layout Section
RLC circuits, steady state response
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Study the effect of series LCR elements in an AC circuit.
 Three different combinations can be studied.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/RCsteadystate.svg
	lyxscale 50
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename schematics/RLsteadystate.svg
	lyxscale 50
	height 2cm

\end_inset


\begin_inset Graphics
	filename schematics/RLCsteadystate.svg
	lyxscale 50
	height 2cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Make connections one by one, as per the drawing
\end_layout

\begin_layout Itemize
Note down the amplitude and phase measurements, in each case
\end_layout

\begin_layout Itemize
Repeat the measurements by changing the frequency.
\end_layout

\begin_layout Itemize
For RLC series circuit, the junction of L and C is monitored by A3
\end_layout

\begin_layout Itemize
For resonance select C = 1uF, L = 10mH and F= 1600 Hz, adjust F to make
 phase shift zero
\end_layout

\begin_layout Itemize
The total voltage across L and C together goes almost to zero, the voltage
 across them are out of phase at resonance
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The applied AC voltage is measured on A1 and the voltage across the resistor
 on A2.
 Subtracting the instantaneous values of A2 from A1 gives the combined voltage
 across the inductor and capacitor.
 We need to use an inductor with negligible resistance for good results.
 The phase difference between current and voltage is given by 
\begin_inset Formula $\triangle\Phi=\arctan\left(\frac{X_{c}-X_{L}}{X_{R}}\right)$
\end_inset

.
\end_layout

\begin_layout Standard
The total voltage, voltage across R and the voltage across LC are shown
 in figure.
 The phasor diagram shows the phase angle between the current and the voltage.
 The inductance used in this experiment is around 10mH, having a resistance
 of 
\begin_inset Formula $20\Omega$
\end_inset

.
 
\end_layout

\begin_layout Standard
At 1600 Hz, 
\begin_inset Formula $X_{c}\approx X_{L}$
\end_inset

 and the voltage across LC is decided by the resistance of the inductor.
 At the resonant frequency, the voltage drop across LC will be minimum,
 decided by the resistance of the inductor.
 The input A3 is connected between L and C, so that the individual voltage
 drop across L and C can be displayed.
\end_layout

\begin_layout Section
Transient Response of RC circuits
\begin_inset CommandInset label
LatexCommand label
name "sec:Capacitor-charging-&"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Plot the voltage across a capacitor, when it is charged by applying a voltage
 step through a resistor.
 Calculate the value of the capacitance from the graph.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/RCtransient.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/RCtransient.png
	lyxscale 70
	height 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
From 
\shape italic

\begin_inset ERT
status open

\begin_layout Plain Layout


\backslash
menuitem{Electrical}
\end_layout

\end_inset


\shape default
 , select 
\shape italic

\begin_inset ERT
status open

\begin_layout Plain Layout


\backslash
menuitem{RC Transient response}
\end_layout

\end_inset


\shape default
 
\end_layout

\begin_layout Itemize
Click on 
\shape italic
0->5V STEP
\shape default
 and 
\shape italic
5->0V step
\shape default
 Buttons to plot the graphs
\end_layout

\begin_layout Itemize
Adjust the horizontal scale, if required, and repeat.
\end_layout

\begin_layout Itemize
Calculate RC time constant.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Applying a 0 to 5V step makes the voltage across the capacitor to rise exponenti
ally as shown in the figure.
 By fitting the discharge curve with 
\begin_inset Formula $V(t)=V_{0}e^{-\frac{t}{RC}}$
\end_inset

 ,we can extract the RC time constant and find the values of capacitance
 from it.
 
\end_layout

\begin_layout Standard
The voltage across a capacitor is exponential only when it is charged trough
 a linear element, a resistor for example.
 When charged from a constant current source, the voltage shows linear increase,
 because 
\begin_inset Formula $Q=It=CV$
\end_inset

 , and voltage increases linearly with time as 
\begin_inset Formula $V=\left(\frac{I}{C}\right)t$
\end_inset

 .
\end_layout

\begin_layout Section
Transient Response of RL circuits
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Explore the nature of current and voltage when a voltage step is applied
 to resistor and inductor in series.
 By measuring the voltage across the inductor as a function of time, we
 can calculate its inductance.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/RLtransient.svg
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/RLtransient.png
	lyxscale 70
	height 4cm

\end_inset


\end_layout

\begin_layout Standard
In an RL circuit 
\begin_inset Formula $V=IR+L\frac{dI}{dt}$
\end_inset

 and solving this will give 
\begin_inset Formula $I=I_{0}e^{-\frac{R}{L}t}$
\end_inset

.
 The coefficient of the exponential term R/L can be extracted from the graph
 of voltage across the inductor.
 The resistance of the inductor coil should be included in the calculations,
\begin_inset Formula $R=R_{ext}+R_{L}$
\end_inset

.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Inductor is the 3000 Turn coil
\end_layout

\begin_layout Itemize
Click on 
\shape italic
0->5V STEP
\shape default
 and 
\shape italic
5->0V step
\shape default
 Buttons to plot the graphs
\end_layout

\begin_layout Itemize
Adjust the horizontal scale, if required, and repeat.
\end_layout

\begin_layout Itemize
Calculate the value of inductance
\end_layout

\begin_layout Itemize
Insert an iron core into the inductor and repeat
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The transient response of the RL circuit is shown in figure.
 The exponential curve is fitted to extract the L/R value.
 The resistance of the coil is measured by comparing it with the known external
 resistance under DC conditions.
 A2 is connected to OD1 for a more accurate measurement of the coil resistance.
\end_layout

\begin_layout Standard
The applied voltages are above zero, but the graph went to negative voltages.
 Why ?
\end_layout

\begin_layout Standard
What was the current before doing the 5->0 step ? What is back EMF ?
\end_layout

\begin_layout Standard
Repeat with two coils in series, by (a) placing them far away (b) placing
 one over the other and (c) after changing the orientation.
 The effect of mutual inductance can be seen.
\end_layout

\begin_layout Section
Transient response of LCR circuits
\begin_inset CommandInset label
LatexCommand label
name "sec:Step-Response-ofRLC"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Explore the oscillatory nature of L and C in series.
 Resonant frequency of series LC circuit is given by 
\begin_inset Formula $\omega_{0}=\frac{1}{2\pi\sqrt{LC}}$
\end_inset

.
 The damping factor is 
\begin_inset Formula $\frac{R}{2}\sqrt{\frac{C}{L}}$
\end_inset

, and it is equal to 1 for critical damping.
\begin_inset Foot
status collapsed

\begin_layout Plain Layout
http://en.wikiversity.org/wiki/RLC_circuit
\end_layout

\end_inset

 Depending upon the value of C/L and R, the response could be under-damped,
 critically-damped or over-damped.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/RLCtransient.svg
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/RLC-curves.png
	lyxscale 60
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure 
\end_layout

\begin_layout Itemize
Start with the coil and 0.1 uF capacitor
\end_layout

\begin_layout Itemize
Click on 5->0V STEP.
 Adjust x-axis and repeat if required.
\end_layout

\begin_layout Itemize
FIT the graph to find the resonant frequency & Damping.
\end_layout

\begin_layout Itemize
Repeat with a resistor between OD1 and the inductor.
\end_layout

\begin_layout Itemize
Repeat the experiment with different values of L, C and R
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
We have used the 3000 turn coil and a 0.1uF capacitor.
 The voltage across the capacitor after a 5 to 0V step is shown in figure.
 The measured resonant frequency tallies with 
\begin_inset Formula $f=\frac{1}{2\pi}\sqrt{\frac{1}{LC}}$
\end_inset

 , within the component tolerance values.
\end_layout

\begin_layout Section
RC Integration & Differentiation 
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
RC circuits can integrate or differentiate a voltage waveform with respect
 to time.
 A square wave is integrated to get a triangular wave and differentiated
 to get spikes at the transitions.
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align center
\begin_inset Graphics
	filename schematics/RCintegration.svg
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename schematics/RCsteadystate.svg
	lyxscale 70
	height 3cm

\end_inset


\end_layout

\begin_layout Standard

\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Select WG triangular wave option
\end_layout

\begin_layout Itemize
Set WG to 500Hz (T = 1mS), R=1k and C = 1uF
\end_layout

\begin_layout Itemize
Adjust the horizontal scale to view more than 4 cycles.
\end_layout

\begin_layout Itemize
Repeat the same for RC differentiator, at 50Hz.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Integration of a triangular waveform gives parabolic shape and differentiation
 gives a square shape.
 The differentiation can only be shown at lower frequency.
 Try these for other wave shapes, for example a squarewave.
 Integrating a square wave should give a triangular wave.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/RCintegration.png
	lyxscale 70
	height 4cm

\end_inset

 
\begin_inset Graphics
	filename pics/RCdifferentiation.png
	lyxscale 70
	height 4cm

\end_inset


\end_layout

\begin_layout Section
Fourier Analysis
\begin_inset CommandInset label
LatexCommand label
name "sec:Fourier-Transform-**"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Learn about Fourier Transform of a signal.
 Time and Frequency domain representations.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Connect SQ1 to A1 and WG to A2.
 Put A1 in AC coupled mode (slide switch on the box)
\end_layout

\begin_layout Itemize
Enable A1 and A2, select 4 volt scale
\end_layout

\begin_layout Itemize
Set both WG and SQ1 to 500Hz
\end_layout

\begin_layout Itemize
Press the FFT button
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
In the Fourier transform plot, frequency is on the x-axis and the y-axis
 shows the relative strength of the frequency components of the signal.
 This is called the frequency domain representation
\begin_inset Foot
status collapsed

\begin_layout Plain Layout
http://en.wikipedia.org/wiki/Fourier_transform
\end_layout

\end_inset

.
 For the sine wave there is only one dominant peak, the smaller ones are
 a measure of distortion of the sine wave.
 
\end_layout

\begin_layout Standard
A square wave function can be represented as 
\begin_inset Formula $f(\theta)=sin(\theta)+\frac{sin(3\theta)}{3}+\frac{sin(5\theta)}{5}+\cdots$
\end_inset

.
 In the Fourier transform of a square wave of frequency 
\begin_inset Formula $f$
\end_inset

 , there will be a 
\begin_inset Formula $3f$
\end_inset

 component (having an amplitude of one third of 
\begin_inset Formula $f$
\end_inset

 ), 
\begin_inset Formula $5f$
\end_inset

 component (amplitude one fifth) etc.
 as shown in the figure.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/sqwaveFFT.png
	lyxscale 70
	height 5cm

\end_inset

 
\begin_inset Graphics
	filename pics/sinewaveFFT.png
	lyxscale 70
	height 5cm

\end_inset


\end_layout

\begin_layout Section
Electromagnetic induction
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Explore the voltage induced across a coil by a changing magnetic field,
 by dropping a small cylindrical magnet into a coil.
 Use a tube to guide the magnet through the coil.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/induction.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/induction-screen.png
	lyxscale 60
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Click on Start Scanning.
 A horizontal trace should appear
\end_layout

\begin_layout Itemize
Drop the magnet through the coil, until a trace is caught.
\end_layout

\begin_layout Itemize
Repeat the process by changing the parameters like magnet strength, speed
 etc.
\end_layout

\begin_layout Paragraph*
Discussion 
\end_layout

\begin_layout Standard
The result is shown in figure.
 The amplitude increases with the speed of the magnet.
 From the graph, we can find the time taken by the magnet to travel through
 the coil.
\end_layout

\begin_layout Standard
The second peak is bigger than the first peak.
 Why ? Where will be the magnet at the zero crossing of the induced voltage?
 Drop the magnet from different heights and plot the voltage vs square root
 of the height.
\end_layout

\begin_layout Chapter
Sound
\end_layout

\begin_layout Standard
Pressure variations, about an equilibrium pressure, transmitted through
 a medium is called sound.
 They are longitudinal waves.
 Moving a sheet of paper back and forth in air can generate these kind of
 pressure waves, like the paper cone of a loudspeaker.
 When the frequency is within 20 to 20000Hz range, we can hear the sound.
 In this chapter, we will generate sound from electrical signals, detect
 them using the built-in microphone (a pressure sensor) and study the properties
 like amplitude and frequency.
 Velocity of sound is measured by observing the phase shift of digitized
 sound with distance.
\end_layout

\begin_layout Section
Frequency response of Piezo
\begin_inset CommandInset label
LatexCommand label
name "sec:Resonance-frequency-of"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Plot the frequency response curve of the Piezo disk by scanning through
 the frequency and measuring the amplitude of the microphone output.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/sound-capture.svg
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/piezo-freq-resp.png
	lyxscale 50
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Make the connections and keep the Mic and the Buzzer facing each other
\end_layout

\begin_layout Itemize
Press START button
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The Frequency Vs Amplitude plot is shown in figure.
 The amplitude is maximum around 3500 Hz.
\end_layout

\begin_layout Section
Velocity of sound
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Calculate the velocity of sound by measuring the pressure variation with
 distance.
 Sound travels as a series of compressions and rarefactions.
 Figure 
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:Sound-waves"

\end_inset

(a) shows the High and Low pressure regions along the direction of travel,
 along with output of a pressure sensor at corresponding positions.
\end_layout

\begin_layout Standard
We can display the pressure variation at any point with respect to the variation
 at the starting point.
 The phase of the microphone output changes as you change its distance from
 the Piezo.
 Moving by one wavelength changes the phase by 360 degrees.
 If the phase changes by 
\begin_inset Formula $X$
\end_inset

 degrees for 
\begin_inset Formula $\triangle D$
\end_inset

 cm change in distance, the wavelength is given by 
\begin_inset Formula $\lambda=\frac{360\times\triangle D}{X}$
\end_inset

 .
 The velocity of sound can be calculated by multiplying the frequency with
 this.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/sound_waves.png
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename schematics/sound-velocity.svg
	lyxscale 70
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Set frequency to resonant maximum by measuring the frequency response 
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Resonance-frequency-of"

\end_inset


\end_layout

\begin_layout Itemize
Keep the Piezo facing the microphone, on the same axis
\end_layout

\begin_layout Itemize
Enable measurement
\end_layout

\begin_layout Itemize
Adjust the distance to make both the traces in Phase
\end_layout

\begin_layout Itemize
Change the distance to make them 180 degree out of phase, that distance
 is half wave length.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
At 3500 Hz, for a 2 cm change in distance the phase changed from 176 to
 102.
 Using the equation, 
\begin_inset Formula $v=f\times\frac{360\times\triangle D}{X}=3500\times\frac{360\times2}{(176-102)}=34054$
\end_inset

 cm/sec.
 It is important to keep the mic and the Piezo disc on the same axis, for
 accurate results.
\end_layout

\begin_layout Section
Sound beats
\begin_inset CommandInset label
LatexCommand label
name "sec:Interference-of-sound"

\end_inset


\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Study the interference of sound from two individual sources.
 Two Piezo buzzers are powered by two different sources, and the sound is
 directed towards the microphone.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/sound-beats.svg
	lyxscale 70
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Set WG to 3500 Hz and SQ1 to 3600 Hz
\end_layout

\begin_layout Itemize
Enable WG and SQ1 separately to check the MIC output
\end_layout

\begin_layout Itemize
Adjust positions of Piezo buzzers, from the mic, to get almost same amplitude
 with both
\end_layout

\begin_layout Itemize
Select both of them to get the beat pattern
\end_layout

\begin_layout Itemize
Press FFT to view the frequency spectrum
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
From figure it can be seen how the low frequency envelope is created.
 Distance between two minimum pressure points., of the envelope, corresponds
 to the beat wavelength.
 The Fourier transform of the output is shown in figure .
\end_layout

\begin_layout Chapter
Mechanics & Heat
\end_layout

\begin_layout Standard
Resonance phenomena is studied using a driven pendulum.
 Value of acceleration due to gravity is measured using a pendulum.
 Cooling of a liquid is studied using a PT100 sensor.
\end_layout

\begin_layout Section
Acceleration due to gravity using Rod pendulum
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measure the period of oscillations of a rod pendulum using a light barrier
 and calculate the value of acceleration due to gravity.
 Period of oscillation of a uniform rod about one end is given by 
\begin_inset Formula $T=2\pi\sqrt{\frac{2\ell}{3g}}$
\end_inset

, where 
\begin_inset Formula $\ell$
\end_inset

 is the length and 
\begin_inset Formula $g$
\end_inset

 is the acceleration due to gravity.
 The pendulum (T-shaped, a knife edge attached to a 6mm dia rod) is made
 to swing between an LED and photo-transistor, connected to expEYES.
 The LED and photo-transistor are mounted on a U-shaped bracket as shown
 in figure.
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align left
\begin_inset Graphics
	filename schematics/rod-pendulum.svg
	lyxscale 60
	height 2cm

\end_inset

 
\begin_inset Graphics
	filename pics/light-barrier-photo.jpg
	lyxscale 50
	width 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Oscillate the pendulum and click on START
\end_layout

\begin_layout Itemize
Repeat with different pendulum lengths.
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The time period is measured 50 times, using a 14.6cm rod pendulum, and the
 average value is 0.627 seconds.
 The calculated value of 'g' is 977.4 
\begin_inset Formula $cm/sec^{2}$
\end_inset

, slightly different from the actual value due to the following reasons.
 The length is measured from the knife edge to the bottom and used in the
 formula.
 But there is a small mass projecting above the knife edge that is not included
 in the calculation.
 Another reason is that the pendulum may not be exactly vertical in the
 resting position.
\end_layout

\begin_layout Section
Angular Velocity of Pendulum
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
To study the nature of oscillations of a pendulum.
 An angle encoder is required for measuring the angular displacement as
 a function of time.
 But using a DC motor as a sensor, we can measure the angular velocity as
 a function of time.
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align center
\begin_inset Graphics
	filename pics/pendulum-screen.png
	lyxscale 50
	width 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Attach some sort of rigid pendulum to the axis of the motor.
\end_layout

\begin_layout Itemize
Connect the motor between A3 and GND
\end_layout

\begin_layout Itemize
Connect 100Ohm resistor from Rg to Ground
\end_layout

\begin_layout Itemize
Oscillate the pendulum and START digitizing
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The observed waveform is shown in figure.
 Fitting it with equation 
\begin_inset Formula $A=A_{0}sin\left(\omega t+\theta\right)*\exp\left(-dt\right)+C$
\end_inset

, using Grace gave an angular frequency of 10 Hz.
\end_layout

\begin_layout Standard
The pendulum should be made with a heavy bob and a light weight rod connecting
 it to the axis of the motor.
 In this case, the DC motor acts like a generator and the voltage is proportiona
l to the instantaneous angular velocity.
\end_layout

\begin_layout Section
Resonance of a driven pendulum
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Demonstrate the resonance of a driven pendulum.
 
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/driven-pendulum.svg
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/resonance-pendulum.jpg
	height 3cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
Make a pendulum using two button magnets and a piece of paper.
 Suspend it and place the 3000T coil near that, as shown in figure.
 
\end_layout

\begin_layout Itemize
Connect the coil between SQ1 and ground
\end_layout

\begin_layout Itemize
Calculate the resonant frequency from the length of the pendulum
\end_layout

\begin_layout Itemize
Scan the frequency around the expected resonance frequency
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
When SQ1 reaches the resonant frequency of the pendulum, the amplitude goes
 up due to resonance.
 A 4 cm (from the center of the magnet to the axis of oscillation) long
 pendulum resonated at around 2.5 Hz, almost tallying with its calculated
 natural frequency.
 The resonant frequency of the pendulum is given by 
\begin_inset Formula $f=\frac{1}{2\pi}\sqrt{\frac{g}{\ell}}$
\end_inset

, where 
\begin_inset Formula $\ell$
\end_inset

 is the distance from the center of the magnet to the point of suspension
 and 
\begin_inset Formula $g$
\end_inset

 is the acceleration due to gravity.
 
\end_layout

\begin_layout Standard
Repeat the experiment by changing the length of the pendulum.
 
\end_layout

\begin_layout Section
Distance Measurement, by ultrasound echo
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Measure distance by measuring the time taken by 40kHz pulse train to echo
 from a hard surface.
\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename schematics/sr04-dist.svg
	lyxscale 70
	height 3cm

\end_inset


\end_layout

\begin_layout Itemize
Keep a flat surface, like a cardboard sheet, around 10 cm from the echo
 module
\end_layout

\begin_layout Itemize
Press START
\end_layout

\begin_layout Itemize
Change the distance with time
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
The distance is calculated from the time taken by a burst of sound to echo
 from the surface kept in front of the module.
 The distance can be measred as function of time, enabling to calculate
 velocity, acceleration etc.
\end_layout

\begin_layout Section
Temperature measurement using PT100
\end_layout

\begin_layout Paragraph*
Objective
\end_layout

\begin_layout Standard
Record the temperature of a liquid by using a Platinum Resistance Thermometer.
 Resistance of a PT100 element is related to the temperature by the equation
 
\begin_inset Formula $R_{T}=R_{0}\left[1+AT+BT^{2}\right]$
\end_inset

, where 
\begin_inset Formula $A=3.9083e-3$
\end_inset

 and 
\begin_inset Formula $B=-5.775e-7$
\end_inset

.
 
\begin_inset Separator latexpar
\end_inset


\end_layout

\begin_layout Standard
\align left
\begin_inset Graphics
	filename schematics/pt100.svg
	lyxscale 70
	height 3cm

\end_inset

 
\begin_inset Graphics
	filename pics/pt100-screen.png
	lyxscale 50
	width 5cm

\end_inset


\end_layout

\begin_layout Paragraph*
Procedure
\end_layout

\begin_layout Itemize
Enter the Gain, Offset error and the Current from CCS
\end_layout

\begin_layout Itemize
Select the temperature range and time intervals
\end_layout

\begin_layout Itemize
Select the required parameters and press START
\end_layout

\begin_layout Paragraph*
Discussion
\end_layout

\begin_layout Standard
Cooling curve of water is shown in figure 
\end_layout

\begin_layout Standard
To measure the resistance of the PT100 element, we connect it from the CCS
 to ground and measure the voltage across it.
 The actual current of CCS should be measured using an ammeter or by measuring
 the voltage frop across an known resistor.
 The input to A3 is amplified 11 times by connecting 1kOhm resistor from
 Rg to Ground.
\end_layout

\begin_layout Standard
The resistance of PT100 is
\begin_inset Formula $100\Omega$
\end_inset

 at 
\begin_inset Formula $0^{0}C$
\end_inset

 .
 It changes nearly 
\begin_inset Formula $0.4\Omega/C$
\end_inset

 , changing the voltage by 0.4 milli volts.
 The 12 bit ADC output changes by 1 LSB for 1.22 mV change in input voltage,
 hence any temperature change less than 3 degrees will not be detected.
 Use an external non-inverting amplifier to increase the resolution.
 The gain of the amplifier should be such that the maximum temperature measured
 should give an output less than 3.3 volts.
 Change the gain field entry accordingly.
\end_layout

\begin_layout Chapter
Coding expEYES-17 in Python
\end_layout

\begin_layout Standard
The GUI programs described in the previous sections are meant for a fixed
 set of experiments.
 To develop new experiments, one should know how to access the features
 of expEYES from software.
 Important function calls used for communicating with the device is given
 below.
 
\end_layout

\begin_layout Paragraph*
Establish Connection
\end_layout

\begin_layout Standard
To access the EYES17 hardware, the python modules for eyes17 must be installed.
 They should be inside a directory named eyes17, that could be in your home
 directory or on the Python PATH.

\series bold
 Every program should start with the following 2 lines
\end_layout

\begin_layout LyX-Code
import eyes17.eyes
\end_layout

\begin_layout LyX-Code
p = eyes17.eyes.open()
\end_layout

\begin_layout Standard
The variable p is the software object, representing the hardware.
 
\end_layout

\begin_layout Standard
The following sections explains the Python function calls to access the
 eyes17 hardware.
 Each function call will be explained with an example usage.
\end_layout

\begin_layout Paragraph
set_pv1(v), set_pv2(v)
\end_layout

\begin_layout Standard
Sets the DC voltages at PV1 and PV2.
 PV1 range is -5 to 5.
 PV2 range is -3.3 to 3.3.
\end_layout

\begin_layout LyX-Code
print p.set_pv1(4) 
\end_layout

\begin_layout LyX-Code
print p.set_pv2(2)
\end_layout

\begin_layout Standard
The value set is printed.
 Measure the voltages using a meter.
\end_layout

\begin_layout Paragraph
get_voltage(input) 
\end_layout

\begin_layout Standard
Returns the voltage at the specified input.
\end_layout

\begin_layout LyX-Code
print p.get_voltage('A1')
\end_layout

\begin_layout LyX-Code
print p.get_voltage('A2')
\end_layout

\begin_layout LyX-Code
print p.get_voltage('A3')
\end_layout

\begin_layout LyX-Code
print p.get_voltage('MIC')
\end_layout

\begin_layout LyX-Code
print p.get_voltage('SEN')
\end_layout

\begin_layout Standard
Connect PV1 to A1 and use the set_pv1() and get_voltage together.
 This function sets the input range by trial 
\end_layout

\begin_layout Standard
and error, depending on the input signal.
\end_layout

\begin_layout Paragraph*
get_voltage_time(input) 
\end_layout

\begin_layout Standard
Returns a tuple, containing the computer's time stamp and the voltage at
 the specified input 
\end_layout

\begin_layout LyX-Code
print p.get_voltage_time('A1')
\end_layout

\begin_layout Paragraph*
get_resistance() 
\end_layout

\begin_layout Standard
Returns the value of resistance connected to SEN, it should be between 100
 Ohm and 100k for reasonable accuracy.
\end_layout

\begin_layout LyX-Code
print p.get_resistance()
\end_layout

\begin_layout Paragraph*
get_capacitance() 
\end_layout

\begin_layout Standard
Returns the value of capacitance connected to IN1 (works well in pF ranges)
\end_layout

\begin_layout LyX-Code
print p.get_capacitance()
\end_layout

\begin_layout Paragraph*
get_version()
\end_layout

\begin_layout Standard
Returns the version number of the Firmware
\end_layout

\begin_layout Standard
print p.get_version()
\end_layout

\begin_layout Paragraph*
get_temperature()
\end_layout

\begin_layout Standard
Returns the temperature of the processor inside eyes17
\end_layout

\begin_layout LyX-Code
print p.get_temperature()
\end_layout

\begin_layout Paragraph*
set_state(OUPUT=value)
\end_layout

\begin_layout Standard
Sets the output of OD1, SQ1 etc.
 Connect OD1 to A1 and run
\end_layout

\begin_layout LyX-Code
p.set_state(OD1=1) 
\end_layout

\begin_layout LyX-Code
print p.get_voltage('A1')
\end_layout

\begin_layout Paragraph*
set_sine(frequency)
\end_layout

\begin_layout Standard
Generates the sinewave of requested frequency on WG (range from 5Hz to 5000Hz).
 All intermediate values are not possible, function returns the actual value
 set.
\end_layout

\begin_layout LyX-Code
print p.set_sine(502)
\end_layout

\begin_layout Standard
502.00803
\end_layout

\begin_layout Paragraph*
set_sine_amp(amplitude)
\end_layout

\begin_layout Standard
The amplitude can be set to 3 pre-defined values of the peak voltage ( 0->
 80mV, 1-> 1V, 2-> 3V)
\end_layout

\begin_layout LyX-Code
p.set_sine_amp(2)
\end_layout

\begin_layout Standard
Sets the amplitude to 3 volts peak.
\end_layout

\begin_layout Paragraph*
set_sqr1(frequency)
\end_layout

\begin_layout Standard
Sets the frequency of SQ1 output (range from 4Hz to 1 MHz).All intermediate
 values are not possible, function returns the actual value set.
\end_layout

\begin_layout LyX-Code
print p.set_sqr1(15030)
\end_layout

\begin_layout Standard
15030.53
\end_layout

\begin_layout Paragraph*
set_sqr1_slow(frequency)
\end_layout

\begin_layout Standard
Sets the frequency of SQ1 output (range from 0.1Hz to 1 MHz).All intermediate
 values are not possible, function returns the actual value set.
 Resolution is high but WG is disabled when SQ1 is operated in this mode.
\end_layout

\begin_layout LyX-Code
print p.set_sqr1_slow(0.5)
\end_layout

\begin_layout Paragraph*
set_sqr2(frequency)
\end_layout

\begin_layout Standard
Similar to set_sqr1() but SQ2 is not available along with WG, only one at
 a time.
\end_layout

\begin_layout Paragraph*
set_sqr1(frequency, dutyCyle)
\end_layout

\begin_layout Standard
Sets the frequency of SQ1 output (range from 0.1Hz to 1 MHz).All intermediate
 values are not possible, function returns the actual value set.
\end_layout

\begin_layout LyX-Code
print p.set_sqr1(1000, 30)          # 1000Hz with 30% duty cycle
\end_layout

\begin_layout Paragraph*
get_freq(input)
\end_layout

\begin_layout Standard
Measures the frequency of a square wave on the input, IN2 or SEN.
 Connect SQ1 to IN2 and run the code
\end_layout

\begin_layout LyX-Code
p.set_sqr1(1000)
\end_layout

\begin_layout LyX-Code
print p.get_freq('IN2')
\end_layout

\begin_layout Paragraph*
duty_cycle(input)
\end_layout

\begin_layout Standard
Measures the duty cycle a square wave on the input, IN2 or SEN.
 Connect SQ1 to IN2 and run the code
\end_layout

\begin_layout LyX-Code
p.set_sqr1(1000, 30)
\end_layout

\begin_layout LyX-Code
print p.duty_cycle('IN2')
\end_layout

\begin_layout Paragraph*
r2ftime(input1, input2)
\end_layout

\begin_layout Standard
Measures the time interval between a rising edge on input1 to another one
 on input2, the inputs can be the same also.
 This can be tested using a square wave.
\end_layout

\begin_layout Standard
Connect SQ1 to IN2 and run
\end_layout

\begin_layout LyX-Code
p.set_sqr1(1000, 30)
\end_layout

\begin_layout LyX-Code
print p.r2ftime('IN2', 'IN2')
\end_layout

\begin_layout Standard
0.0003
\end_layout

\begin_layout Standard
The 1kHz square wave with 30% duty cycle has a Period of one millisecond
 and stays HIGH for .3 milliseconds.
\end_layout

\begin_layout Paragraph*
multi_r2rtime(input, numCycles)
\end_layout

\begin_layout Standard
Measures the time interval between rising edges on input1.
 Time between 2 edges is one cycle.
 Number of cycles to be measured also can be specified, default value is
 1.
 The allowed values are 1,2,4,8,12,16,32 and 48.
 This can be tested using a square wave.
\end_layout

\begin_layout Standard
Connect SQ1 to IN2 and run
\end_layout

\begin_layout LyX-Code
p.set_sqr1(1000)
\end_layout

\begin_layout LyX-Code
print p.multi_r2rtime('IN2', 8)
\end_layout

\begin_layout Standard
0.008
\end_layout

\begin_layout Paragraph*
select_range(channel, range)
\end_layout

\begin_layout Standard
The input range of A1 and A2 can be set from 
\begin_inset Formula $\pm0.5V$
\end_inset

 to 
\begin_inset Formula $\pm16V$
\end_inset

 fullscale, using the programmable gain amplifiers.
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 4)         # 4volt maximum
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 8)         # 8 volt maximum
\end_layout

\begin_layout Paragraph*
select_range(channel, range)
\end_layout

\begin_layout Standard
The input range of A1 and A2 can be set from 
\begin_inset Formula $\pm0.5V$
\end_inset

 to 
\begin_inset Formula $\pm16V$
\end_inset

 fullscale, using the programmable gain amplifiers.
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 4)         # 4volt maximum
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 8)         # 8 volt maximum
\end_layout

\begin_layout Paragraph*
capture1(Input, Number of samples, time interval)
\end_layout

\begin_layout Standard
Digitizes the specified input.
 The number of samples could be upto 10000.
 The time gap between two consecutive samples id given in microseconds (range
 2 to 1000 usec).
\end_layout

\begin_layout LyX-Code
print p.capture1('A1', 5, 5)
\end_layout

\begin_layout Standard
will print two arrays of time and voltage.
 
\end_layout

\begin_layout Standard
We need to plot the graph of the output for a better understanding.
 This can be done using the matplotlib module, imported using the pylab
 interface.
 Connect WG to A1 with a wire and run;
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code
p.set_sine_amp(2)
\end_layout

\begin_layout LyX-Code
p.set_sine(1000)
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 4)
\end_layout

\begin_layout LyX-Code
t,v = p.capture1('A1', 300, 10)
\end_layout

\begin_layout LyX-Code
plot(t,v)
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout Standard
The output of this code is given below.
\end_layout

\begin_layout LyX-Code
\begin_inset Graphics
	filename pics/sine.png
	lyxscale 50
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
capture2(Number of samples, time interval)
\end_layout

\begin_layout Standard
Digitizes the inputs A1 and A2 together.
 The number of samples could be upto 10000.
 The time gap between two consecutive samples id given in microseconds (range
 2 to 1000 usec).
\end_layout

\begin_layout Standard
Connect WG to A1 and a diode from A1 to A2.
 Run the code below
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code
p.set_sine_amp(2)
\end_layout

\begin_layout LyX-Code
p.set_sine(1000)
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 4)
\end_layout

\begin_layout LyX-Code
t,v,tt,vv = p.capture2(300, 10)
\end_layout

\begin_layout LyX-Code
plot(t,v)
\end_layout

\begin_layout LyX-Code
plot(tt,vv)
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout Standard
The output of this code is given below.
\end_layout

\begin_layout Standard
\begin_inset Graphics
	filename pics/halfwave.png
	lyxscale 60
	height 4cm

\end_inset

 
\begin_inset Graphics
	filename pics/capture4.png
	lyxscale 60
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
capture4(Number of samples, time interval)
\end_layout

\begin_layout Standard
Digitizes the inputs A1,A2,A3 and MIC together.
 The number of samples could be upto 10000.
 The time gap between two consecutive samples id given in microseconds (range
 2 to 1000 usec).
\end_layout

\begin_layout Standard
Connect WG to A3 and run the code given below.
 Result is shown above.
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code
p.set_sine_amp(2)
\end_layout

\begin_layout LyX-Code
p.set_sine(1000)
\end_layout

\begin_layout LyX-Code
p.select_range('A1', 4)
\end_layout

\begin_layout LyX-Code
res = p.capture4(300, 10)
\end_layout

\begin_layout LyX-Code
plot(res[4],res[5])        # A3
\end_layout

\begin_layout LyX-Code
plot(res[6],res[7])        # MIC
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout Paragraph*
set_wave(frequency, wavetype)
\end_layout

\begin_layout Standard
If wavetype is not specified, it generates the waveform using the existing
 wave table.
 If wavetype is specified ('sine' or 'tria')
\end_layout

\begin_layout Standard
corresponding wavetable is loaded.
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code
p.set_wave(1000, 'sine')
\end_layout

\begin_layout LyX-Code
p.set_wave(100)       # Sets 100Hz using the existing table
\end_layout

\begin_layout LyX-Code
x,y = p.capture1('A1', 500,50)
\end_layout

\begin_layout LyX-Code
plot(x,y)
\end_layout

\begin_layout LyX-Code
p.set_wave(100, 'tria')  # Sets triagular wave table and generates 100Hz
\end_layout

\begin_layout LyX-Code
x,y = p.capture1('A1', 500,50)
\end_layout

\begin_layout LyX-Code
plot(x,y)
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout Paragraph*
load_equation(function, span)
\end_layout

\begin_layout Standard
Makes the wave table using the quation.
 Connect WG to A1 and run the code below.
 The output also is shown below.
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
def f1(x):
\end_layout

\begin_layout LyX-Code
    return sin(x) + sin(3*x)/3 
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
p.load_equation(f1, [-pi,pi])
\end_layout

\begin_layout LyX-Code
p.set_wave(400)
\end_layout

\begin_layout LyX-Code
x,y = p.capture1('A1', 500,10)
\end_layout

\begin_layout LyX-Code
plot(x,y)
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout LyX-Code
\begin_inset Graphics
	filename pics/loadEquation.png
	lyxscale 60
	height 4cm

\end_inset

  
\begin_inset Graphics
	filename pics/loadTable.png
	lyxscale 60
	height 4cm

\end_inset


\end_layout

\begin_layout Paragraph*
load_table(function, span)
\end_layout

\begin_layout Standard
The wave table can be loaded with a 512 element array.
 Connect WG to A1 and run the code below.
 After taking the absolute value, the table starts with 256, goes down to
 zero and then goes upto 255, tracing a triagular wave.
 The tableoutput also is shown above.
\end_layout

\begin_layout LyX-Code
from pylab import *
\end_layout

\begin_layout LyX-Code
x = arange(-256, 256)
\end_layout

\begin_layout LyX-Code
x = abs(x)
\end_layout

\begin_layout LyX-Code
p.load_table(x)
\end_layout

\begin_layout LyX-Code
p.set_wave(400)
\end_layout

\begin_layout LyX-Code
x,y = p.capture1('A1', 500,10)
\end_layout

\begin_layout LyX-Code
plot(x,y)
\end_layout

\begin_layout LyX-Code
show()
\end_layout

\begin_layout Standard

\end_layout

\end_body
\end_document
