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Are these inductors?

If so, can anybody estimate their ratings? Or is there a way I can measure them? I'm looking for something around a 4mH inductor to use in "Simplest Ever DC-DC Boost 12v to 73v" instructable by "pyrohaz". Also, are these potential inductors the same as the ones found in CFL light bulbs? And one more thing, why does the small one have 4 wires coming out, the medium one has 2 wires, and the big one has 10?

Picture of Are these inductors?
Photo on 2010-09-07 at 15.25.jpg
Photo on 2010-09-07 at 15.27.jpg
CrLz6 years ago
They are inductors and transformers. (There is more than meets the eye...)

At the most basic, you've got a wire wound around a ferrite, inductor core.
  
You medium coil, with one wire wound around the core is most likely acting as a RF Choke Coil.  The wire is wound around a ferrite core to filter-out ("choke") high frequency AC currents.  A dumb-old chunk of inductive metal that is too big to "vibrate" in high frequencies is a cheap, simple way to filter out those nasty frequencies.

I'd suspect the other two are acting as transformers.

The first is most likely a balun transformer, a transmission line transformer.

Last is probably acting as a straight-forward transformer, wound on a ferrite toroid core.

Sorry I can't help you more with measuring the inductance.  Did you notice pyrohaz's comment

If you are unsure of the the inductor size, just try tweaking the oscillation capacitor until you get the highest voltage :)*

Maybe he can help answer your question.  His Instructable has lots of similar questions<>advice in the comments.




choke 5700 SERIES.jpgBalun41.giftoroid Transformer.jpg
lemonie6 years ago

yes.
If you re-wind them as per- that I'ble, it should work something-like that.

l
Incidentally, it would work as an inductor if you only use one pair of wires.
They are all transformers of some description. The multiple wires may be separate tappings for the transformers, or they may be the result of "multi-filar" winding the transformer to reduce capacitance effects in the windings. Best thing to do is measure the inductance with a pulse generator and a scope.