Measurement of Self Inductance accurately by Anderson's Bridge

  Procedure:

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

  2. Set the value of the unknown air cored coil from 'Set Inductor Value' tab by clicking on 'Set' button.

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

  4. Choose the values of   r1, R2, R3, R4, r, and C from the resistance and capacitance 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 Inductor Value' tab and click on 'Simulate'. Observe calculated values of unknown Inductor (L1) and it's Internal Resistance (R1). Also observe the Quality factor (or Q-factor) of the coil which is defined as   `(omegaL)/r`.  Where, `omega=2pif`.

    7. N.B.:-
    Range of C = 100`pF` to 11.111`uF` (in steps of 100`pF`).
    Range of r1, R2, R3, R4 and r =  `1  Ω` to `11111110  Ω`  (in steps of 1 `Ω`)

Tutorials Point

Voltage:

Frequency:

V

Hz

`Ω`

`Ω`

`Ω`

`Ω`

`Ω`

`F`

`mV`

C

  • L1:

    R1:

    `Ω`

    `mH`

    Set the actual values of L1:
    Range of air cored inductor (L1) is 0 `mH` to 30 `mH`
    with internal resistance 1`Ω`
    Enter the L1 value and click on the Set button.
    L1 (in `mH`): 
    0 `mH`   30 `mH`
  • The current voltmeter reading is:   mv.
    Now simulate to get:
    Inductor value (in `mH`):
    Resistance value (in `Ω`):
    Quality Factor:
CONTROLS
   r1 : 1 Ohm     11.11111 MΩ
   R2 : 1 Ohm     11.11111 MΩ
   R3 : 1 Ohm     11.11111 MΩ
   R4 : 1 Ohm     11.11111 MΩ
   r : 1 Ohm     11.11111 MΩ
   C : 100 pF     11.111uF