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Question
Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.
Solution 1
- For a parallel combination of two coils, the current through each parallel inductor is a fraction of the total current and the voltage across each parallel inductor is the same.
- As a result, a change in total current will result in less voltage dropped across the parallel array than for any one of the individual inductors.
- There will be less voltage drop across parallel inductors for a given rate of change in current than for any of the individual inductors.
- Less voltage for the same rate of change in current results in less inductance.
- Thus, the total inductance of two coils is less than the inductance of either coil.
Solution 2
When two inductors with inductances L1 and L2 are connected in parallel, the equivalent inductance is given by
`1/"L"_"equivalent" = 1/"L"_1 + 1/"L"_2`
which is less than the individual inductance value L1 and L2.
As a result, the inductance of two parallel coils is smaller than the inductance of either coil.
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