How to Read a Potentiometer

A potentiometer is a variable resistor that may function as a rheostat or voltage divider. In order to read one, all that is necessary is to have an ohmmeter or a multimeter on an ohmmeter setting.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Potentiometer
• Multimeter
• Paper and pencil or computer spreadsheet

1. Place your multimeter on the appropriate ohmmeter setting. It must be higher than that of the resistance rating of the potentiometer.

2. 

   Place one lead of the multimeter on the left terminal of the potentiometer, and the other on the wiper or middle part. Record the value.

3. 

   Now place one lead of the multimeter on the right terminal of the potentiometer, and the other on the wiper. Again, record the value.

4. 

   Finally, set one lead of the multimeter on the potentiometer's left terminal, and the other on its right terminal. Record the value once more. It will approximately equal that of the maximum resistance indicated on the package the device came in.

Tips & Warnings

• If you don't know the resistance of the potentiometer, place the multimeter on the lowest setting and gradually increase it until you get a reading. You may wish to use alligator clips on your multimeter leads so that they will not slip off while you are recording values.
• It is not unusual for inexpensive potentiometers to be off by as much as 50 percent of their rated value when they are measured.

References

• Getting Started in Electronics; Forrest Mims III