Paul Burridge wrote:

On Tue, 13 Jul 2004 23:48:53 GMT, "Highland Ham"
wrote:


What's the quickest and simplest way of running an 8 ohm earpiece to a
32 ohm earpiece output socket without suffering too much power loss?

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Any small transformer with a winding ratio 2 : 1 . Check with low
voltage -50 Hz , 1 V in ......0.5 V out. Ratio is not all that critical .
You can also use a tranformer's single winding with a centre tap .


Thanks, Frank. Turns out on further investigation the circuit
specifies * two* 32 ohm insets in series for 64 ohms altogether. I've
still only got an 8 ohm earpiece, though. So that's an 8:1
transformation which adds up to.... a tap a quarter way along one
winding? Or is it three-quarters. Or of course a full, 4:1
transformer, I suppose. I always get confused with transformations,
for some reason. :-/

The winding ratio goes as the square root of the impedance ratio,
because you're transforming the current UP at the same time your
transforming the voltage DOWN. So you need a root-8:1, or about 3:1.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com