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
    20,766
    2,536
    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...

    [​IMG]

    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
    20,766
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    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
     
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