What Is a Potentiometer?
A potentiometer (pot) is a three-terminal resistor that can be adjusted by hand. It's the most common adjustable component for settings like volume and brightness.
How Does It Work?
Two terminals connect to a resistive track, and the middle terminal (wiper) connects to a contact point moving along that track. As the wiper slides, the resistance between the middle terminal and the ends changes.
Use as a Voltage Divider
Thanks to its three terminals a potentiometer works like an adjustable voltage divider: a voltage that depends on the setting is taken from the middle terminal.
Types
| Type | Feature |
|---|---|
| Linear (B) | Resistance proportional to the angle |
| Logarithmic (A) | Suited to human perception, like audio |
| Rotary / Slide | Physical form of movement |
Where Is It Used?
Volume level, brightness, speed adjustment, sensor (angle/position) and calibration.
The Digital Potentiometer Alternative
As an alternative to the mechanical potentiometer, there are digital potentiometers whose value is set by a microcontroller over I2C/SPI. Having no moving parts, they don't wear out; they allow remote and automatic adjustment.
Common Mistakes
- Confusing linear/log: a log pot is chosen for audio, a linear pot for general adjustment.
- Drawing current: a pot is used as a voltage divider; high current wears out the wiper.
- Over-forcing it: turning it past the mechanical limits damages the pot.
Frequently Asked Questions
What's the difference between a linear and a logarithmic pot?+
What's the difference between a potentiometer and a rheostat?+
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