Re: 220V transformers on 120V?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-ian-dot-org>

On Wed, 29 May 2002, Tesla list wrote:
> 	I don't know much about 555 circuits, but how are you measuring the
> transistor output?  If you're using a scope on the transistor output
> (essentially no load on the transistor), you may get funny readings.
> This has happened to me before.  I was running on 12VDC.  I put a 50 ohm
> resistor across the transistor (output to ground), and then got a good
> square wave on the scope.  You don't need the resistor if you're driving
> a "real" load, of course.  Just a thought.

Yes, resistors helped.. I did some more fiddling around and got
the transistor output to be close enough to the square wave
input that I am happy.  A cap in series shifts it to be AC,
but making a sine wave is harder... and I'm not sure the input
to the transformer has to be sine anyway.

Is there a good reference for powering transformers out there?  I
have a dozen or so small ones and have varied success in getting
output from them.  I read that either high voltage or low voltage
with a high frequency will do the same job, but I am not sure
of why.  How does one figure out the proper power input into
an unmarked transformer?  There has to be a good web page or
book I can read to show me what I'm missing.  Thanks!

-- 
Ian Smith
www.ian-dot-org
www.sportsmogul-dot-com