Lab 07_ Measuring Capacitance Without Using DMM

Lab 07: Measuring Capacitance Without Using DMM
Parth Priyank- 71288773 9th March 2022
Wanqi Lu-93724441


Objective: Measure the capacitance of the capacitor without using the DMM (Digital Multimeter )

Clarify Objective:
- Capacitor: Is a device used to store electrical energy in the electric field.
- Capacitance: Property of an electric conductor where it is the ratio for the amount of
charge which can be stored by the capacitor.

Therefore,

𝐶 = � , 𝑉where Q represents charge in the capacitor and V represents the Voltage of the
Capacitor. We can also find capacitance of the capacitor by using the formula:

τ = � × 𝐶. This is the formula for time constant τ, where R represents the resistance and C
represents the Capacitance of the capacitor.

- In order to calculate the the capacitance of the capacitor, we would setup a RC circuit and use
the formula for a discharging capacitor which is:
−𝑡/�𝐶
𝑉(𝑡) = 𝑉 (� ), where V (t) is the voltage across the capacitor at time t, R represents the
0
resistance of the resistor in the RC circuit and C represents the capacitance of the capacitor used
in the RC circuit.

Therefore, after rearranging the formula to make the capacitance (C) as the subject, new formula
is:
−𝑡
𝐶 = , where V (t) is the voltage across the capacitor at time t, R represents the resistance
�𝑙𝑛( 𝑉(𝑡)𝑉 )
0


of the resistor in the RC circuit and C represents the capacitance of the capacitor used in the RC
circuit.

- A second method can be employed to calculate the capacitance of the capacitor which is
comparatively easier, less time consuming and more accurate according to the results found. As
we know that time constant τ is the time taken for capacitor is gain its 63.2 % of its max charge,
Once we setup a RC circuit and form a wave respectively for it on the oscilloscope, we can
directly find the time constant τand therefore using the formula:

τ = � × 𝐶, we can find the capacitance of the capacitor used in the RC circuit.

Explore tools:
Tools Physical Parameters Resolution Range Usage



1
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, Oscilloscope Frequency (Hz) 5V ± 0.01 V To visually display
Voltage (V) and measure the
voltage

Function Generator Frequency (Hz), 1 MHz - 10 Hz 1.16 ± 0.01 V To make the
Voltage (V) Oscilloscope easy
to read and
understand.

Capacitor Capacitance (F) - - Store electrical
energy in the
electric field

Digital Multimeter Voltage (V) 0.01 Ω to 100 k± 0. 001 𝑘Ω Determine the
Resistance (Ω) 0.001 V 100V ± 0. 001 𝑉 Resistance of the
resistor used in RC
circuit

Wires - - - Used to connect
components on the
breadboard

DC Power Supply Power(Watts) 1250 Watts 5.087 ± 0.002 V To supply power to
the circuit by
connecting to the
breadboard.

Breadboard - - - Parts would be
connected on the
Breadboard to form
a RC circuit



Relate Quantities:
Method 1

- In order to calculate the the capacitance of the capacitor, we would setup a RC circuit and use
the formula for a discharging capacitor which is:
−𝑡/�𝐶
𝑉(𝑡) = 𝑉 (� ), where V (t) is the voltage across the capacitor at time t, R represents the
0
resistance of the resistor in the RC circuit and C represents the capacitance of the capacitor used
in the RC circuit.

Therefore, after rearranging the formula to make the capacitance (C) as the subject, new formula
is:




2
This study source was downloaded by 100000899606070 from CourseHero.com on 02-23-2026 02:38:11 GMT -06:00


https://www.coursehero.com/file/155630034/Lab-07-Measuring-Capacitance-Without-Using-DMM-docx/