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What technology changed
- Thread starter DPittman
- Start date
SparWeb
Active Member
They are not equivalent devices.
That is an awesome rheostat you have there. Take good care of it!
I think that's also called a "variac" but maybe someone more knowledgeable needs to correct me.
The wiper bar on the top is covering the "output" spec but I assume it can vary from 0-120VAC output, based on the 2.2A current rating and 270VAC power rating.
If you don't want it, I have a use for it.
The other thing is a cheap potentiometer made in China. Variable resistor. Useful but not very special.
That is an awesome rheostat you have there. Take good care of it!
I think that's also called a "variac" but maybe someone more knowledgeable needs to correct me.
The wiper bar on the top is covering the "output" spec but I assume it can vary from 0-120VAC output, based on the 2.2A current rating and 270VAC power rating.
If you don't want it, I have a use for it.
The other thing is a cheap potentiometer made in China. Variable resistor. Useful but not very special.
DPittman
Ultra Member
Ah yes my preliminary research indicated right of the bat that they are not the same thing. I just haven't quite figured out yet what application the old rheostat was made for. I just knew that someone on this forum would know these things. I will continue to read.They are not equivalent devices.
That is an awesome rheostat you have there. Take good care of it!
I think that's also called a "variac" but maybe someone more knowledgeable needs to correct me.
The wiper bar on the top is covering the "output" spec but I assume it can vary from 0-120VAC output, based on the 2.2A current rating and 270VAC power rating.
If you don't want it, I have a use for it.
The other thing is a cheap potentiometer made in China. Variable resistor. Useful but not very special.
VicHobbyGuy
Ultra Member
A Variac isn't the same as a rheostat; it's a transformer and a rheostat is a variable resistor. The windings on a Variac are copper wire; it's a type of transformer and the wiper is selecting differing numbers of turns on one of the windings. A wire-wound rheostat winding is made of resistance wire. BTW, depending on how you connect them, most Variacs will output voltages from zero to a voltage greater than the input, IME.
Yes, a variac is a variable transformer and a rheostat is a variable resistor.
Think of the Variac as a very efficient variable voltage AC power supply. That supply can also be rectified and filtered to easily become a variable voltage DC power supply.
I had a nice one around here someplace but it has disappeared.......
Think of the Variac as a very efficient variable voltage AC power supply. That supply can also be rectified and filtered to easily become a variable voltage DC power supply.
I had a nice one around here someplace but it has disappeared.......