What is a potentiometer and why is it used? What is the cost of a 10K potentiometer?

How to Use a Potentiometer

As far as we know resistors should always have two terminals but, why a potentiometer has three terminals, and how do we use these terminals? It is very easy to understand the purpose of these terminals by looking at the diagram below.

The diagram shows the parts present inside a potentiometer. We have a resistive track whose complete resistance will be equal to the rated resistance value of the POT.

As the symbol suggests a potentiometer is nothing but a resistor with one variable end. Let us assume a 10k potentiometer, here if we measure the resistance between terminal 1 and terminal 3 we will get a value of 10k because both the terminals are fixed ends of the potentiometer. Now, let us place the wiper exactly at 25% from terminal 1 as shown above and if we measure the resistance between 1 and 2 we will get 25% of 10k which is 2.5K, and measuring across terminals 2 and 3 will give a resistance of 7.5K.

So terminals 1 and 2 or terminals 2 and 3 can be used to obtain the variable resistance and the knob can be used to vary the resistance and set the required value.


  • Voltage and Current Control Circuits
  • Used as volume control knobs in radios
  • Tuning or controlling circuits
  • Analog input control knobs

2D Diagram (Model P232)

Potentiometer Dimensions

Potentiometer Pin Configuration

Pin No.  Pin Name Description
1 Fixed End This end is connected to one end of the resistive track
2 Variable End This end is connected to the wiper, to provide variable voltage
3 Fixed End This end is connected to another end of the resistive track



  • Type: Rotary a.k.a Radio POT
  • Available in different resistance values like 500Ω, 1K, 2K, 5K, 10K, 22K, 47K, 50K, 100K, 220K, 470K, 500K, and  1 M.
  • Power Rating: 0.3W
  • Maximum Input Voltage: 200Vdc
  • Rotational Life: 2000K cycles

Note: Complete Technical Details can be found in the Potentiometer datasheet given at the end of this page.


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