difference between these two parts

[wayne]

are pots the same thing as rheostats?...
this topic has more to do with electronics so i m not sure if its supposed to be in General Hardware..but if its not, then mods, please move it

thanks

 

[BlindedByScience]

...both are variable resistors. "Rheostats" typically handle far more current than a "potentiometer"...but the difference is largely semantics.

Regards - B.B.S.

 

[defcom_1]

Rheostat:
http://www.overclockercafe.com/Articles/Rheostat/
Potentiometer:
http://www.allaboutcircuits.com/vol_6/chpt_3/7.html

Rheostat: Variable resistor
Potentiometer:

Potentiometers find their most sophisticated application as voltage dividers, where shaft position determines a specific voltage division ratio.

-http://www.allaboutcircuits.com/vol_6/chpt_3/7.html

 

[agent420]

Although very similar, I think technically a rheostat is the basic 2 terminal device, with an open ended resistor and a wiper, while a potentiometer is the 3 terminal device with connections at both ends of the resistor and the wiper.

A potentiometer can be wired as a rheostat by wiring the wiper to one end of the resistor.

 

[BlindedByScience]

...that picture of a "rheostat" sure looks like a potentiometer with one terminal unconnected.....

You are correct in that rheostat's are typically two terminal devices, while pots are typically three terminal devices.

Like I said, it's largely semantics.......

B.B.S.

 

[agent420]

I agree it's semantics, I think the rheostat is the older father of the pot from way back in the day, when the 3rd terminal wasn't required for the uses at the time.

 

[groggory]

If I remember, I'll stop by jk electronics and take some pics of real rheostats. There are some beefy mofos over there.

 

[awdark]

Hrmm I know I can dig up some potentiometers.. does anyone know why I usually end up with smoke when I try to reduce the voltage of something lets say a fan with a potentiometer?
If I follow the basic ideas of that site above about Potentiometers it is suppose to work right? or will I need a voltage regulator in combination with that or something of that sort?

 

[Acceptable_Risk]

Originally posted by awdark
Hrmm I know I can dig up some potentiometers.. does anyone know why I usually end up with smoke when I try to reduce the voltage of something lets say a fan with a potentiometer?
If I follow the basic ideas of that site above about Potentiometers it is suppose to work right? or will I need a voltage regulator in combination with that or something of that sort?

The ideal situation would be an LM317 or similar part with a potentiometer on the adjustment leg. Just the pot in series with the fan ought to do something, though. Are you sure it rated for the current the fan pulls?

 

[groggory]

Originally posted by awdark
Hrmm I know I can dig up some potentiometers.. does anyone know why I usually end up with smoke when I try to reduce the voltage of something lets say a fan with a potentiometer?
If I follow the basic ideas of that site above about Potentiometers it is suppose to work right? or will I need a voltage regulator in combination with that or something of that sort?

I have a page for you to read...

http://lbccsec.com/general_upload/LM317T.htm

Your solution should work though as long as you have the right rated pot. When I get a chance, I'll measure the pots on my vantec fans. See what they used. They're not large pots, but definetely have some metal to dissipate a little bit of heat. Not the tiny trimmer pots or anything.

Hope this helped