Brian Hill wrote:
Lets also not forget that we never use a variac with out a volt meter
because not everyone's line voltage is the same and we can't just blindly
trust the markings on the variac either. The best variacs have voltmeters on
them but most don't. A lot of old radios were not designed for 120 volt so
there good to have just for testing but one needs to know exactly what
voltage is being put out.

And lets not use one without an ammeter either. You can still fry an
unknown radio at low voltage.

-Bill