Here in circuit left side above are unknown Resistor(R1) and inductor L1) , which values has to measure.
Left side below are variable known resistance (R2) and inductance (L2) .
Right side resistors above(R3) and below R4) are known.
By varying variable resistance and inductance, we have to reach at null point in ammeter.
And then after :
R1= (R2*R3)/R4
L1 = (R3*L2) /R4
These equation is applicable when balance condition is achieved.
