It is also a modification of the Maxwell-Wien Bridge and is particularly useful if the phase angle of the inductive impedance ɸm = tan-1(ωL/R) is large. The network is shown in figure 1. It is seen that, in the case, a comparatively smaller series resistance R1 is used instead of a parallel resistance (which has to be of a very large value).
Z2 = R2
Z3 = R3 + jωL3; Z4 = R4
Balance condition is Z1Z3 = Z2Z4
Separating the reals and the imaginaries, we obtain
Solving these simultaneous equations, we get
The symmetry of expression should help the readers to remember the result even when branch elements are exchanged.