Cursitor Doom wrote:

Trevor Wilson wrote:

**Just disconnect the transformer from the mains supply. Connect a
multimeter from primary to secondary and measure the resistance. It
should read infinity.

If it were that simple I'm sure someone would have already suggested it.

** It is that simple and someone just did.

AFAIK - and I could be wrong I admit; it's not my field - most
transformers, isolation type or not, will pass this test so it doesn't
really tell us anything.


** Only isolation transformers will pass such a test.

The other kind ( aka auto-transformers) will not.


..... Phil