Instructables

How to measure resistance of a Potentiometer?

Picture of How to measure resistance of a Potentiometer?
Many of us have used potentiometer in our day to day life, for example varying the volume of your music system by rotating the knob, controlling the brightness of your television by pressing a button on the remote. Behind all these mechanism Potentiometer is there which is controlling the sound level or the brightness level of your gadget.

Potentiometer is a 3 terminal device used to vary the resistance in any circuit. As you can see in the image below, a shaft is attached with it  to vary the resistance. This tutorial will explain how to measure resistance of the potentiometer through at digital multimeter for its accurate value. If you want to know more about this electronic component, check this pin diagram, and an insight on working of potentiometer


Apparatus required:

1. Digital Multimeter
2. Linear potentiometer
 
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Step 1: Knowing the potentiometer

Picture of Knowing the potentiometer
Turn the potentiometer and you will see the maximum resistance value of the potentiometer engraved over it. Here 1Mega ohm is the maximum value of resistance this potentiometer has.

Step 2: Making connections to the multimeter

Picture of Making connections to the multimeter
Connect the multimeter probes according to their polarity. The red wire goes to the positive while the black one goes to the ground or neutral.

Step 3: Adjusting the multimeter for measuring resistance

Picture of Adjusting the multimeter for measuring resistance
In this multimeter, 4M ohm is the starting range for measuring resistance in Mega ohms. As our pot is of 1 Mega Ohm, 4M ohm range is more than sufficient to measure 1 Mega ohm.

Step 4: Measuring total resistance in the potentiometer

Picture of Measuring total resistance in the potentiometer
We can see the maximum resistance of this pot by connecting the probes at both the ends. Here .795 is the maximum resistance this potentiometer has. The measuring range of the multimeter is same as what we have seen in the Step 2.

Step 5: Connecting probes to the lugs of potentiometer.

Picture of Connecting probes to the lugs of potentiometer.
The positive probe is connected to the middle lug while the negative probe is connected to the first lug. Position of the lugs can be changed but it will affect the change of resistance i.e. changing the terminals will change the minimum and maximum point of the resistance.

Step 6: Maximum resistance

Picture of Maximum resistance
The knob is turned to its maximum position and by connecting the probes to the terminals of the potentiometer; digital multimeter displays the value of resistance.