A: The calculation of inductance value is similar to resistance calculation if the inductors are used in series or parallel.

① The total inductance will be increased when an inductor is used in series, and the total inductance is the sum of all inductors. (L = L1 + L2 + L3 +...)

② The total inductance will be decreased when an inductor is used in parallel, but the current will be higher. The total current is the sum of the currents in each inductor, it can be used in circuits with a higher current.

L=1/(1/L1+1/L2+1/L3+1/L4+……)