Networks Analysis and Synthesis - Engineering

Q1:

The equivalent inductance measured between the terminals 1 and 2 for the circuit shown in the figure is

A L1 + L2 + M

B L1 + L2 - M

C L1 + L2 + 2M

D L1 + L2 - 2M

ANS:D - L1 + L2 - 2M

L = L1 + L2 - 2M because currents are opposing.