🚀 go-pugleaf

"Mike Diack" <moby@kcbbs.gen.nz> wrote in message
news:3eccb0e6.54530502@News.xtra.co.nz...
> I'm redesigning a device for blind navigation that I first designed a
> decade or so ago, which requires a transformer to drive an
> electrostatic transducer (sweeping 100..50KHz, around 100v P/P driven
> from a 6v P/P source).
> My first iteration used a (hand wound) Philips 10mm 3E25 toroid. I
> gave one of my original samples to a local transformer outfit and
> asked them to make me something smaller (and tidier!)
> Everything they came back with was bigger than my original.
> I have seen a polarisation tranny inside an AKG C460 microphone which
> is smaller than the size of a frozen pea. Admittedly this tranny only
> has to handle a single frequency wheras mine carries a sweep, but who
> can make trannies like that or where can the cores be sourced
> (preferably surface mount)
> cheers
> M

RM4 or EFD10 is the smallest I know. But since you have a large ratio of
input/output voltage, what about a standard inductor - then you add a extra
winding onto. Like this:

http://www.elytone.com.tw/transformers-2.asp (ET-578: 3mmx5mm)

You may not get very high coupling of the windings, but since this is very
low power - who cares :-)

Cheers

Klaus