Anderson's Bridge 3w2r1b

SELF INDUCTANCE OF A GIVEN COIL BY ANDERSON’S BRIDGE AIM: To determine the self inductance of a given coil by Anderson’s bridge. Apparatus: Battery, Resistance box, Galvanometer, Capacitor, Inductance coil. L=C [ QR +r ( R+ S ) ] Henry

Formula:

Where L Self inductance of the coil (H) C Capacitance of the capacitor (F) R Resistance () r Varying resistance () Procedure: a) DC Part 1) Electrical connections are made as shown in the fig.1. 2) In the first part of the experiment DC source and the galvanometer are used in the circuit. 3) The arm’s P, Q, R are the resistance in the post office box. In the other arm the given self inductance coil is connected. 4) Dc balance is obtained with r=0 by adjusting the value of P, Q, R. two trails b) AC Part 5) The Dc source is replaced by an audio oscillator and the galvanometer by the ear phone 6) By keeping the resistance P, Q, R same and r is suitably adjusted till the minimum sound is heard in the ear phone.

7) Then self inductance is calculated by using the relation L= C [Q R+r(R+S)] Henry. 8) The experiment is repeated by keeping the resistance P, Q, R same as that of the DC part. Result: The self inductance of the given coil is found using Anderson’s bridge = H

Circuit diagram

Tabular Column:

For C = 0.1µF S=

Trial no

P in

Q in 

r in 

L=C [ QR +r ( R+ S ) ] 10-3 Henry



Tabular Column 2: Trial no

R in

QR P

P in

For C=0.5µF

Q in 

R in

r in 

S= 

Calculation:

QR P

L=C [ QR +r ( R+ S ) ] 10-3 Henry