Pro Audio Design Forum

I need a fairly large inductance in a small package, so I thought about using a miniature audio transformer with the windings connected in series. Is there a way to figure out what the inductance would be, knowing the impedance and the DC resistance (or should I just buy one and measure it)?
Thanks!
Bruno2000

I have no practical experience with this. I don't know if you can use transformer action to get something for nothing. I wouldn't think there is an easy substitute for copper and iron to give large LF signal handling.

When in doubt, try it and see what happens.

JR

I think you'll have to buy a meter. I think there are some ways you can rig a meter set-up, but owning a meter is probably worth it in the long run. I think CJ or PRR may have posted a method at PP.

Thanks folks,
Looks like plan B. Buy the transformer and measure it.
I've seen some LC meters on eBag that will go up to 20H for about $30. Anybody ever used one of these?
Bruno2000

I'm not sure what your application is but perhaps prototype up the circuit you want to use the transformer/inductor in, and see how it acts.

I suspect there may be no free lunch here.

JR

Bruno2000 wrote:I need a fairly large inductance in a small package

How big and how small?

Thinking out loud, without knowing what you are trying to do, it is common to use opamps with a small capacitor to mimic a large capacitor, perhaps a similar trick could multiply a small inductor to look like a bigger one.

Also gyrators, use opamps with small caps to mimic inductors, perhaps another option.

If dealing with a lot of current or voltage, you may need to use a real inductor.

JR

I have a hunch we may be making a vintage inductor-based EQ based on a popular design.

Funny I still have some inductors back in my lab I bought to build a 5 band GEQ from a kit in popular electronics back in the '70s. I never built it or any Inductor based EQ, and don't even like the common gyrator based EQs (gyrator as shunt to ground between opamp + and - inputs).

If trying to recreate a classic design, I suspect it would be useful to use the same general components. It's not nice to fool father physics.

JR