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Simple Circuit analysis of potentiometer problem

  1. Apr 11, 2012 #1
    Really simple problem but:

    If you have a circuit with a power supply, a potentiometer and an output voltage taken from midway down the potentiometer and just after it; would this act like a potential divider with the potentiometer acting as two resistors?
     
  2. jcsd
  3. Apr 11, 2012 #2
    Yes, It will act like a two resistors voltage divider.
    But only without the load resistor.
    attachment.php?attachmentid=46117&stc=1&d=1334159055.png
     

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  4. Apr 11, 2012 #3
    Thanks for the help
     
  5. Apr 11, 2012 #4

    berkeman

    User Avatar

    Staff: Mentor

    Keep in mind that is only true if the potentiometer wiper is connected to a high impedance. If there is a finite input impedance to the circuit that follows the wiper, then that impedance needs to be included in the circuit analysis to figure out the wiper voltage.

    Also, it is not good design practice to connect a high impedance to a potentiometer wiper. There is a minimum wiper current needed to keep the potentiometer reliable. This is a good reference for using potentiometers:

    http://www.google.com/url?q=http://www.bourns.com/pdfs/trmrpmr.pdf&sa=U&ei=vLOFT5nRKsSQiAK8vIH3BA&ved=0CBAQFjAA&usg=AFQjCNFDFeeCAZLuimBWRSHq48nFEuHt3Q [Broken]

    .
     
    Last edited by a moderator: May 5, 2017
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