In article ,
(DoN. Nichols) wrote:

According to Joseph Gwinn :
In article ,
(DoN. Nichols) wrote:

[ ... ]

http://www.triadmagnetics.com/Catalog/index.html

Mouser carries a lot of their transformers, but they don't stock
the isolation transformers so I can't pull down any images to see how
they compare to mine. Mine is old enough so it has only a 2-pin jack,
and a "cheater-cord" socket for power to the transformer -- which would
match what you would expect to find in a TV repair shop anyway. :-)

Yeah. I have seen them. But I wonder if it's really Triad, or a front
for Chinese stuff only.

I don't know -- but you might try digging through their web
site, if your browser is happier with it than mine is.

It isn't, neither of them, but the problem is at Triad's end - the URLs
for the images are bogus.


Of course -- my isolation transformer is old enough to predate
the supposed Chinese takeover. :-)

I bought a 3-winding "Stancor" audio
transformer that claimed to be able to handle 1,000 volts between any
two windings, but when I measured the capacitance between windings, it
was a few nanofarads between two of them, and 100 picofarads between
those two and the other. Hmm. I bet the first two are bifilar wound,
and will handle only a few hundred volts, whatever the magnet wire
insulation can handle. The datasheet also gave bandwidth and
distortion, but failed to specify the power level at which this
distortion was achieved. I emailed Stancor, and got an incomprehensible
reply: they confounded DC resistance with power, although they did admit
that perhaps the 1,000 volts wasn't for all windings. I never got a
reply to my email asking for clarification of the unclear parts.

It sounds as though you hit a marketing guy, not a real tech. :-)

Yes, but I had the impression that they no longer had any engineers to
ask.

The experience makes me reluctant to use Stancor for anything, because I
can no longer trust their catalog descriptions. By the way, the audio
transformer works perfectly well. The only problem is that it isn't
even close to matching its description, or being what I needed, which
means that as a builder of one-off projects, every purchase would be a
drama. It was not always thus.

Joe Gwinn