How to Test Potentiometer(Find Bad Potentiometer)

• A potentiometer is a manually adjustable variable resistor with 3 terminals. Two terminals are connected to both ends of a resistive element, and the third terminal connects to a sliding contact, called a wiper, moving over the resistive element.The position of the wiper determines the output voltage of the potentiometer. The potentiometer essentially functions as a variable voltage divider. The resistive element can be seen as two resistors in series(potentiometer resistance), where the wiper position determines the resistance ratio of the first resistor to the second resistor.

Method #1:

Required Parts:  Multimeter, Potentiometer

• First, turn ON the multimeter.
• Find out the rating of your potentiometer. The total resistance in ohms should be written on the side or bottom.
• Set your multimeter to a setting higher than the total resistance of the potentiometer(Low cost multimeter) or select the resistance mode in your multimeter(High cost multimeter). For example, if your potentiometer is rated at 1,000 ohms, set your ohmmeter to 10,000 ohms.
• Connect the probes of your multimeter on the two ends like in the above image.
• Now, rotate the potentiometer knob using your finger it will change the resistance value High to Low or Low to High in the multimeter. if the resistance value is change the potentiometer is good condition or is not change the resistance value potentiometer is bad condition.

Method #2:

Required Parts:  Multimeter, Potentiometer, 9V Battery or any DC power supply

• First, turn ON the multimeter and select DC voltage mode in your multimeter.
• Put the probes of your multimeter on the two ends like in the above image.
• Now, rotate the potentiometer knob using your finger it will change the Battery DC voltage High to Low or Low to High in the multimeter. if DC voltage is change, the potentiometer is good condition or is not change DC voltage, the potentiometer is bad condition.

Method #3:

Required Parts:  Multimeter, Potentiometer, Stepdown transformer

• First, turn ON the multimeter and select AC voltage mode in your multimeter.
• Connect the probes of your multimeter on the two ends like in the above image.
• Now, rotate the potentiometer knob using your finger it will change the Transformer AC voltage High to Low or Low to High in the multimeter. if AC voltage is change, the potentiometer is good condition or is not change AC voltage, the potentiometer is bad condition.

Method #4:

Required Parts:  Multimeter, Potentiometer, 9V Battery or any DC power supply

• First, connect all connection like in this image.
• Now, rotate the potentiometer knob using your finger it will change the DC motor speed High to Low or Low to High. if DC motor speed is change, the potentiometer is good condition or is not change DC motor speed, the potentiometer is bad condition.

Method #5:

Required Parts:  Multimeter, Potentiometer, Stepdown transformer

• First, connect all connection like in this image.
• Now, rotate the potentiometer knob using your finger it will change the Lamp light source High to Low or Low to High. if Lamp light source is change, the potentiometer is good condition or is not change Lamp light source, the potentiometer is bad condition.