24 Feb
1999
24 Feb
'99
3:04 a.m.
At 02:58 AM 2/24/99 +0000, Lawrence wrote:
I used isolating transformers in electronics lab (more
than 15 years ago)
and
had them explained at that time. I've forgotten
their functioning. IIRC they
are an ordinary transformer, altered to provide "isolation" from ground (via
your body). I have several large transformers. How difficult would it be to
build one from these.
An isolation transformer just has its output winding which isn't grounded,
unlike the mains AC. This is so if you (or another transformerless circuit)
touch it and are grounded, you don't complete the circuit.
If you have 2 similar transformers with an isolated secondary (not an
autotransformer), you can connect them back to back to form a isolation
transformer. As an extreme and not recommended because of the HV, I have
seen this done with microwave oven transformers. This would be much easier
than removing an existing secondary and winding you own isolation winding.
Of course, if you want a single custom transformer, rewinding is an option.
-Dave