The Variac

[pwdrive]

The subject of the variac came up recently on another thread so here is a quick insite to the variac, pluses and pitfalls:

http://sound.westhost.com/articles/variac.htm

{Mod edit: Updated link: http://sound.whsites.net/articles/variac.htm}

Lawrence

[Radio Fixer]

The bit about the brush not causing shorted turns was interesting and something I had never thought about.

thanks Gary

[pwdrive]

Hi Gary, I read that bit also, all the pro's and con's in the article seem to be valid as far as I can see, I sometimes wonder about some of the reference stuff on the web though when I am copying and posting links, there is a lot of miss information out there. I am trying to find some authoritative info on the Humdinger pot or resistor network to post as these were quite common in some AC sets/amps etc. I assume it's basically an artificial center tap to chassis and as such the equal but opposite field on the heater lines cancells out? The HRO receiver uses one.

Lawrence.