# Variable Resistor

Discussion in 'General Electronics Chat' started by khanz, Apr 9, 2008.

1. ### khanz Thread Starter Member

Mar 24, 2008
21
0
Hi all,
It's a basic question about variable resistor. First How to use a variable resistor. Second why there are three pins of a variable resistor. Instead of three I think two will be enough.

2. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
You can use two of the three leads, but if you need a variable voltage divider then 3 is necessary. For example this circuit needs exactly that...

The other advantage of 3 pins is you can select clockwise or counterclockwise to increase or decrease the resistance.

3. ### pander New Member

Apr 10, 2008
2
0
>The other advantage of 3 pins is you can select clockwise or >counterclockwise to increase or decrease the resistance.

New to posting to the forum, so if I make a mistake, oops.

I beg to differ with you. You were correct regarding voltage division, but even a two-terminal pot will increase or decrease the resistance based on turning it.

4. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
If you connect to one set of pins the resistance will increase clockwise, the other set the resistance will increase counter counterclockwise. We are not talking 2 pin pots, but three pins where only two are used. 3 pins are the norm in potentiometers.

5. ### Dave Retired Moderator

Nov 17, 2003
6,960
145
Have a look at something called a "Rheostat".

Dave