Measurement of Self-Inductance (High Quality factor ) by Hay's Bridge

  Procedure:

  1. Set the voltage (V=3V) and Frequency (500Hz) and set the unknown inductor value from 'Set inductor 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 inductor value' tab and click on 'Simulate'. Observe calculated values of unknown inductor (Lx) and unknown internal resistance of the inductor. Also observe the Quality factor of the unknown coil, which is defined as `(2*pi*f*L)/R`.

Tutorials Point

  • Set the actual values of Lx:
      Enter the Lx values and click on the set button.
       Lx (in H): 
    0 H   3 mH
  • The current voltmeter reading is:   mv. Now simulate to get:
         Inductor value (in mH):
    Resistance value (in ohm):
    Quality Factor of unknown coil:
CONTROLS
R2(1 Ohm) 11.1 MOhm
R3(1 Ohm) 11.1 MOhm
R4(1 Ohm) 11.1 MOhm
C4(10 nC) 1.11 uC