# Voltage of a lemon cell

Objective

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

Procedure

- Click on A1 to measure voltage

- Measure the voltage with and without the 1k resistor

Discussion

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 ?

What is the internal resistance of the cell ?

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 ?