Study of Capacitors in Series and Parallel Circuits

Capacitor: Stores electrical energy in the form of an electric field between its plates. The capacitance ๐ถ C is given by

๐ถ = ๐‘„ ๐‘‰ C= V Q โ€‹

where ๐‘„ Q = charge stored, ๐‘‰ V = voltage across capacitor.

Series Connection:

1 ๐ถ ๐‘’ ๐‘ž = 1 ๐ถ 1 + 1 ๐ถ 2 + 1 ๐ถ 3 + โ€ฆ C eq โ€‹

1 โ€‹

= C 1 โ€‹

1 โ€‹

+ C 2 โ€‹

1 โ€‹

+ C 3 โ€‹

1 โ€‹

+โ€ฆ

(Equivalent capacitance decreases; total is less than the smallest capacitor).

Parallel Connection:

๐ถ ๐‘’ ๐‘ž = ๐ถ 1 + ๐ถ 2 + ๐ถ 3 + โ€ฆ C eq โ€‹

=C 1 โ€‹

+C 2 โ€‹

+C 3 โ€‹

+โ€ฆ

(Equivalent capacitance increases; total is the sum of all).

Charging/Discharging: When a capacitor charges through a resistor:

๐‘‰ ๐‘ ( ๐‘ก ) = ๐‘‰ ( 1 โˆ’ ๐‘’ โˆ’ ๐‘ก / ๐‘… ๐ถ ) V c โ€‹

(t)=V(1โˆ’e โˆ’t/RC )

When discharging:

๐‘‰ ๐‘ ( ๐‘ก ) = ๐‘‰ ๐‘’ โˆ’ ๐‘ก / ๐‘… ๐ถ V c (t)=Ve โˆ’t/RC

where ๐‘… ๐ถ RC is the time constant (in seconds).

To verify the relationship of equivalent capacitance for capacitors connected in series and in parallel.

To measure the charging and discharging behavior of a capacitor through a resistor.

To compare experimental results with theoretical values.

DC Power Supply / Battery (6โ€“12 V)

Capacitors (e.g., 10 ยตF, 22 ยตF, 47 ยตF)

Resistor (1 kฮฉ โ€“ 10 kฮฉ for charging/discharging)

Voltmeter (or Digital Multimeter)

Stopwatch (or oscilloscope for accurate time measurement)

Connecting wires, breadboard, switch

Part A: Capacitors in Series

Connect capacitors ๐ถ 1 , ๐ถ 2 , ๐ถ 3 C 1 โ€‹

,C 2 โ€‹

,C 3 โ€‹

in series across the supply.

Measure voltage across the combination and across each capacitor.

Calculate ๐ถ ๐‘’ ๐‘ž C eq โ€‹

theoretically and compare with measured.

Part B: Capacitors in Parallel

Connect capacitors ๐ถ 1 , ๐ถ 2 , ๐ถ 3 C 1 โ€‹

,C 2 โ€‹

,C 3 โ€‹

in parallel.

Measure voltage across each capacitor (should be equal to supply voltage).

Calculate and compare ๐ถ ๐‘’ ๐‘ž C eq โ€‹

(theoretical vs measured).