How to Measure Resistance of a Potentiometer?


Introduction: 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

Step 1: 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

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

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

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.

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

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.

Step 7: Varying the Resistance

The knob of the potentiometer is turned anticlockwise and the resistance of the potentiometer is decreased.

Step 8: Minimum Resistance

As the knob is rotated to its minimum position resistance also comes to its minimum value.



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    hi, i am doing an experiment where i have use a 10k pot. but when i keep the circuit on for few hours then i found my pot. became faulty and the value i set previously has change.

    Can any one tell me why my pot. fails?

    1 reply

    Depends on the load. pots are only designed for small currents. If you connect a high current circuit, it will heat the resistive slider track, and cause the resistance to change, and eventually toast the pot altogether

    794? Isn't it supposed to measure 1M or within 10 percent of it?

    2 replies

    That is a good question. You show 1M ohm pot in first image but then you show 794 ohm as it's max... explain.

    Its because in the setting he used on the multimeter it measures up to 4Mohm. The pot is around 1M, so it shows 0.794Mohm.

    So, if I understand it. A 15k potentiometer turned to its minimum would be o resistance. So, if you wanted a pot to read 60 ohms at the minimum, you would put a 60 ohm resister in line on the 15k pot? You would at least reach a min of 60 ohms but w/o calculating it would not reach 15K at the max.

    2 replies

    Correct, a 60Ω resistor in series with the potentiometer would do. At max, total resistance would be 15'06KΩ (± tolerances).

    i dont mean to be rude, but just from personal usages, they always take a little bit, dependent on the pot.

    Handy tutorial! I'm curious though, what determines the resistance? Is it greater exposure between the pot.'s sliding plate and the contact, or less? (Does greater surface contact generate more resistance, or less?)

    Also, I find it a bit confusing that you use positive and neutral as voltage designations for the multimeter leads, shouldn't it be positive and negative? Technically ground isn't neutral, it's an alternate positive (as in positive charge, not positive voltage relative to another voltage) where electricity can flow in case of a short.

    1 reply

    A potentiometer works where the connection between leg 1, and leg 3 are connected by a semi-resistant plate/ribbon etc, and leg 2 is connected to a dial that moves along it, gathering a voltage where it has less or more resistance. leg 1 - leg 3 being the maximum resistance.