Discharge of Electric Capacitors and the Verification of its Series and Parallel Connections

 

The aim of the experiment

Experiment with the tools

a battery

capacitances

wires

Multimeter

Steps to conduct the experiment

Activity 1: equivalent capacitance by direct measurements for two 

capacitors connected in series and in parallel.

  Use two capacitors with different capacitance and record the given value in the table below. 

  Use the multimeter to measure their values and record the measured values 

 Use equation 5 and equations 6 to find the equivalent capacitance as per given and measured values. 

  Use direct measurement to measure the equivalent capacitance as they are connected in series and in parallel and report these values in 

the table below.

Activity 2: equivalent capacitance by discharging the capacitors in series configurations. 

  Set up the circuit by choosing a pair of capacitors and connect them in series as shown in the figure.

  Before the experiments be sure that the multimeters are connected right and the capacitors are uncharged. 

 Set the output voltage of the power supply to a value between 10 and 20 Volt to be the initial value 𝑉0.

  Bring the switch to the charging position. As no resistors in the charging loop, the voltage on the capacitor will read directly the applied voltage on the capacitors 

  Bring the switch to discharge position and observe the decrease of the voltage on the capacitor and on the resistors as they are parallel. 

  Record the voltage each 20 seconds, and record the measurements in the given table 

  Continue to measure the voltage with time until the voltage value reaches 1V on the capacitor. Do not stop measuring the time by the stopwatch for whole experiment.

  On a graphical paper, Plot V on the vertical axis and the time on the horizontal axis and observe the logarithmic decreasing behavior. 

  Now plot ln(V)=f(t) graph for charging and determine the time constant of the circuit using the slope of the graph. 

  From the time constant, determine the equivalent capacitance of the capacitors and compare it with those reported in the above table. 

  Calculate the error.

Activity 3: equivalent capacitance by discharging the capacitors in parallel configurations.

  Repeat the same experiment while the capacitors are connected in parallel as shown in the figure.