# Electronic components: Potentiometers

> Learn how a potentiometer works as a variable resistor: rotate it to output any fraction of the input voltage, a handy way to regulate circuits by hand.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2021-03-12 | Topics: [Arduino](https://flaviocopes.com/tags/electronics/) | Canonical: https://flaviocopes.com/electronics-components-potentiometers/

A potentiometer is a tiny component that has 3 connectors: 2 on one side, 1 on the other side:

![Small black potentiometer with rotating shaft and two connector pins on one side](https://flaviocopes.com/images/electronics-components-potentiometers/IMG_2918.jpg)

![Larger black potentiometer lying on its side showing the three connector pins and rotating shaft](https://flaviocopes.com/images/electronics-components-potentiometers/IMG_2921.jpg)

The two connectors are the input, they are connected to the negative and to the positive, and the opposite one is the output.

Rotating potentiometer we can have on output a fraction of the voltage difference we have in the input pins.

This is because the potentiometer is a resistor we can modify the resistance of. In this case I have a 10kΩ potentiometer:

![Black 10k ohm potentiometer with visible rating label and ribbed rotating knob](https://flaviocopes.com/images/electronics-components-potentiometers/IMG_2923.jpg)

See this simulation: if we have the potentiometer at full left (counterclockwise), on the output pin we have a 9V difference between the output pin and ground, because the potentiometer is working at 100% as a 10kΩ resistance and absorbs all the current:

![Circuit simulation showing potentiometer at full left position outputting 9.00V on breadboard](https://flaviocopes.com/images/electronics-components-potentiometers/Screen_Shot_2020-12-06_at_15.01.33.png)

If we change the potentiometer value at full right, on the output pin we have 9V because the potentiometer does not absorb any current. It works like a wire, applying 0 resistance.

![Circuit simulation showing potentiometer at full right position outputting 0.00V on breadboard](https://flaviocopes.com/images/electronics-components-potentiometers/Screen_Shot_2020-12-06_at_15.01.38.png)

Having the potentiometer at 50% gives 1/2 of the starting tension in the output pin:

![Circuit simulation showing potentiometer at middle position outputting 4.50V on breadboard](https://flaviocopes.com/images/electronics-components-potentiometers/Screen_Shot_2020-12-06_at_15.01.27.png)

Potentiometer are handy for many reasons, on their own, but they are also used in integrated circuits to help us regulate the output, like in this case with a sound sensor where the potentiometer is the blue box we can regulate with a screwdriver:

![Red sound sensor breakout board with blue potentiometer and microphone component for adjustment](https://flaviocopes.com/images/electronics-components-potentiometers/IMG_2922.jpg)