Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

What is the difference in the use as a potentiometer vs a rheostat?

I’m no expert in electronics, but I do toy around a little as a hobby. I’m familiar with the use of rheostats to vary resistance, but don’t really understand the reason for the third pin on a pot. What kind of applications are all 3 pins used for, and what function does it serve?

3 Answers

Relevance
  • Dixon
    Lv 7
    6 months ago

    A potentiometer is named for it's property of producing a variable voltage, ie electrical potential. A voltage is applied across the full resistance and the variable potential is between the moveable terminal and one end.  

    Attachment image
  • 6 months ago

    the three terminals act as a voltage divider.  see drawing. The pot replaces the two resistors on the left but allows continuous adjustment.

    for two resistors

    Vout = Vin(R2) / (R1+R2)

    for pot with k being percent rotation from 0 to 100%

    Vout = kVin/100

    used, for example, as level controls in audio.

    Attachment image
Still have questions? Get your answers by asking now.