Measurement of Capacitance by Schering Bridge

  Procedure:

  1. Apply Supply voltage (3V) from the signal generator with arbitrary   frequency.

  2. Set the unknown Capacitance value from 'Set Capacitor Value' tab by clicking on 'Set' button.

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

  4. Choose the values of   C2, C4, R3 and R4 from the capacitance and   resistance box. Varry the values to some particular values to achieve   "Null".

  5. Observe the millivoltmeter pointer to achieve "Null" or closest to  "Null".

  6. If "Null" is achieved, switch to 'Measure Capacitor value' tab and   click on 'Simulate'. Observe calculated values of unknown   Capacitor (C1) and it's Internal Resistance (r1). Also observe the   Dissipation factor of the unknwown capacitor which is defined as   `omega*C*r`.   Where, `omega=2pif`.

    7. N.B.:-
    Range of C2 and C4 = 100`pF` to 11.111`uF` (in steps of 100`pF`).
    Range of R3 and R4= `1  Ω` to `11111110  Ω`  (in steps of 1 `Ω`)

Tutorials Point

Voltage:

Frequency:

V

Hz

`Ω`

`Ω`

`F`

`F`

`mV`

  • C1:

    r1:

    `Ω`

    `uF`

    Set the actual values of C1: (r1 value is fixed at 20 Ohm)
    Enter the C1 values and click on the set button.
    C1 (in `muF`): 
    0.0001 `uF`   100 uF
  • The current voltmeter reading is:   mv. Now simulate to get:
         Capacitor value (in `muF`):
    Resistance value (in `Ohm`):
    Dissipation Factor:
CONTROLS
   R3 : 1 Ω     11.11111 MΩ
   R4 : 1 Ω     11.11111 MΩ
   C2 : 100 pF     11.111uF
   C4 : 100 pF     11.111uF