[R-390] Question about VARIAC

[rbethman]

Barry,

The impedance of a transformer "usually" does NOT come into play UNTIL 
there is a short-circuit condition.

Variacs/autotransformers, have a current rating based on conductor size, 
"primarily", and can be run throughout the variable ranger that they are 
built for.  The number of turns used, determines the voltage out.  You 
are not matching an impedance as we are accustomed to with RF.  Power 
transformers are really a different animal.

Bob - N0DGN

Barry wrote:
> I guess what I was getting at was impedences.  If I were to tap the input at 
> one turn (or two or three), then I assume this would appear as a very low 
> impedence and wouldn't work very well (most likely incurring a very heavy 
> current draw and hopefully trip the circuit breaker before burning out the 
> transformer.  If there were double, triple, etc., the amount of turns, this, 
> too, would affect the input impedence, would it not?
>
> I guess what I was trying to say is that I figure there's a point where the 
> number of turns matters but just wasn't sure where that point is.  Is that 
> incorrect?
>
> Thanks,
> Barry - N4BUQ 
>   

-- 
Bob - NØDGN