Bacic Electronic components...........

[subbuindia]

What is the difference between variable resister and rheostat?

 

[thannara123]

Rheostat handles more current ,variable resistor too low


what is the difference between a potentiometer and a variable resistor? - All About Circuits Forum

 

[alexxx]

What is the difference between variable resister and rheostat?

Rheostat is a a two-terminal variable resistor.

Potentiometer - Wikipedia, the free encyclopedia

Hope this helps.

 

[subbuindia]

Thanku very much sir..,
but rheostat has only two terminals. Then, how can it act as varying device?

 

[alexxx]

but rheostat has only two terminals. Then, how can it act as varying device?

Well you could take a look at the posted image at post #3. Potentiometer on the left has three terminals. Staying on the rheostat part of the image (right side), you can see an arrow in the middle of the rheostat. When you change rheostat's resistance, this arrow can travel from the left (R=0) to the right (R=max). Assuming a perfect linear relation between distance and ohmic value, then the arrow in the middle means R/2.
You could construct a rheostat from a potentiometer, by shorting the middle terminal with one of its side terminals.
Finally you could spot another difference between the left and the right part of the image. Potentiometer is used to regulate load's voltage and rheostat is used to regulate load's current.

Hope it is more clear for you now.

 

[subbuindia]

Well sir......,
is it (arrow) treat as 3rd terminal?

 

[alexxx]

Well sir......,
is it (arrow) treat as 3rd terminal?

For potentiometer yes. For rheostat no, there are only two terminals. Maybe the below image could make you understand this better:

As you can see, the third terminal of the potentiometer on the right side is unconnected in this topology, so clearly now we have only two terminals.
Potentiometer as a rheostat : DC CIRCUITS