10KHz-55Khz transformer

I presume you mean 'reasonably flat frequency response'. I made an ultrasonic drive transformer with a large ferrite toroid and bifilar windings. The toroid was about 80mm OD, cross section maybe 15 x 10mm. Can't recall the number of turns, or the actual LF rolloff, but it was 'several KHz'. It went to well above 50, and handled a heap of watts.

All this will also depend on what power capability you require, btw.

Sure. Best would be to get some #77 ferrite toroids. Amidon would be one source. Maybe 3/4" O.D. if you don't have to transfer a lot of power, else get a fat one. If you want to be extra good you can twist the windings to make it bifilar. The ARRL Handbook usually has some nice pictures in there on how to wind it, probably also on the web somewhere.

It can also be done with other cores, for example pot cores scrapped out of computer power supplies.

Hello Kieth,

Whether this is simple depends on some other specifications. I am thinking of power (voltage and current) to be transferred, isolation voltage and capacitance (between windings), DC current through windings, etc..

When the isolation is functional only (so no electrical safety is involved), and requirements with capacitance are not that stringent, it can be easily done up to several hundreds VA. However when there must be very low capacitance or (for example) 3500V double insulation safety requirement, it will be more difficult to keep low both linear and non-linear distortion.

Maybe you can provide us some more information.

Best regards,

Wim PA3DJS

This device is called current compensated inductor and has two windings of equal numbers. Used in power filters and such.

Rene

In American that would be called "common-mode choke". But the core saturates real quick and you have to check the breakdown voltage between the windings. It's usually not very high.