Experiment Description

Experiment

Experiment E06    Charging and Discharging a Capacitor at a Constant Rate

Objectives
  • Learn how to calculate the charge stored in a capacitor by charging or discharging it at a constant rate
  • Illustrate how to keep the charging and discharging currents constant
  • Show that the voltage across a capacitor is proportional to the charge stored in it
  • Determine the capacitance of a capacitor directly from its definition
Description
In this activity, you will adjust the resistance of an RC circuit to keep the current constant until the charging or discharging process is completed.

In Experiment 1, you will charge a capacitor using a constant current. The current is kept constant manually by carefully adjusting the variable resistor. You will measure the time for fully charge the capacitor.

Experiment 2 is similar to Experiment 1. Again you will charge the capacitor at a constant rate. But, this time, you will record the variation of voltage with time.

In Experiment 3, you will discharge the capacitor at a constant rate. You will set the resistance to the highest and reduce it as the capacitor discharges.

Experiment 4 is similar to Experiment 3. Again you will discharge the capacitor at a constant rate. But, this time, you will record the variation of voltage with time.
Apparatus
variable resistor (0 - 50 kOhm) [1]
microammeter (100 mA base meter) [1]
voltmeter (5 V) [1]
capacitor (2200 mF) [1]
battery box with 2 dry cells [1]
switch [1]
stop watch [1]
multimeter (on request) [1]
shunt (1 A) (on request) [1]
Experiment