Determine the equivalent inductance (L_eq) for the given circuit.

Concept

When 'n' inductors are connected in series, the equivalent inductance is given by:

\(L_{eq}=L_1+L_2.........L_n\)

When 'n' inductors are connected in parallel, the equivalent inductance is given by:

\({1\over L_{eq}}={1\over L_1}+{1\over L_2}.........{1\over L_n}\)

Calculation

Given, 4mH and 3mH are connected in series.

\(L_{1}=4+3=7\space mH\)

Now, this 7 mH and 42 mH are connected in parallel.

\(L_{2}={42\times 7\over 42+7}=6\space mH\)

This 6 mH, 3 mH and 5 mH are connected in series.

\(L_{eq}=6+3+5=14\space mH\)