Tapped inductors

[mhuss]

Is there any practical difference between using a single tapped inductor or using multiple series equivalent-value inductors (or separate parallel inductors)? I remember from AC electronics 101 that inductance adds in series.

I would think the 'unused' taps would be much like the unused taps on an output transformer, with voltage across them but no effect as long as no load is connected to the other taps.

[Helmholtz]

Yes inductance adds in series.

With ideal inductors and only one tap connected, the same results can be obtained from a tapped inductor and series connected single inductors.

With real world inductors things like DCR, saturation, DC bias dependency and self-capacitance (resonant frequencies) may make a difference.

Also a tapped inductor is an autotransformer, so when more than one tap is connected, there will be interaction.

Best explain your application.

[catalin gramada]

The main practical diference I see is you.ll get more residual resistance using multiple coils. Is easy to get more inductance just with few turns more rather than to add tens or hundred of turns on the other coil added to get same result. Second, exposed area to EM field proportional with number of coils was used..More don't forget coils prone to couple in between so phisical arangement matters...Just a few.

[mhuss]

The target application is an old speaker crossover, a switch and a 3-tap inductor is used to control the mid/horn content (see, e.g., JBL LX5). 3.85 mH total, so thicker wire, fewer windings. I'm not actually building one, just curious.