Measurement of Capacitance by Wien Series Bridge

  Procedure:

  1. Set the voltage (V=3V) and Frequency (50Hz) and set the unknown capacitance value from 'Set Capacitor Value' tab by clicking on 'Set' button.

  2. Then switch on the supply to get millivoltmeter deflection.

  3. Now vary the values of R2, R3, R4 and C4 from the control box below or directly put the values in the boxes of respective elements.

  4. Observe the millivoltmeter pointer to achieve "NULL".

  5. If "NULL" is achieved, switch to 'Measure Capacitor Value' tab and click on 'Simulate'. Observe calculated values of unknown capacitance (C1) and unknown internal resistance (R1) of the capacitor. Also observe the Dissipation factor of the unknown capacitor, which is defined as `w*C*R`. where, `w=2*pi*f`.

    6. N.B.:-
    Range of C4=100`pF` to 11.111`uF` (in steps of 100 `pF`).
    Range of R2, R3 and R4= `1  Ω` to `11111110  Ω`  (in steps of 1 `Ω`)

Tutorials Point

Voltage:

Frequency:

V

Hz

`Ω`

`Ω`

`F`

`Ω`

`mV`

  • Set the actual values of C1: (R1 value is fixed at 5 `Ω`)
      Enter the C1 values and click on the set button.
       C1 (in `uF`): 
    0.001 `uF`   0.1 `F`

    C1=

    R1=

    `Ω`

    `uF`

  • The current voltmeter reading is:   mv. Now simulate to get:
         Capacitor (C1) value (in uF):
    Resistance (R1) value (in `ohm`):
    Dissipation Factor:
CONTROLS
   R3 : 1 `Ω`     11.11111 MΩ
   R4 : 1 `Ω`     11.11111 MΩ
   R2 : 1 `Ω`     11.11111 MΩ
   C4 : 100 `pF`     11.111`uF`