On Tue, 10 Nov 2015 11:21:37 -0000, Dave Plowman (News) wrote:

In article ,
Tough Guy no. 1265 wrote:
A Variac is a variable voltage transformer. And entirely different
device.

No, it's an auto transformer where you can move the tap. The coil is in
the same configuration.

All girls who attend The High School wear green blazers.
Therefore all girls who wear green blazers attend the High School.

Stupid analogy. You're talking about something which is a subset of another, then saying you can't reverse the assumption. I didn't reverse the assumption, I never said all auto transformers were Variacs, I said a variac is a special kind of auto transformer.

--
A patient complained to his doctor, "I've been to three other doctors and none of them agreed with your diagnosis."
The doctor calmly replied, "Just wait until the autopsy, then they'll see that I was right."