Rotary encoder

A rotary encoder is a device that can keep track of how much something has turned. This is called its angular position. That information is useful to know how far a motor has turned, for example.

An incremental rotary encoder

Rotary encoders are often used in manufacturing and robotics. This is because they need things to be measured and controlled very accurately.

Basic types

Absolute

An absolute encoder always keeps track of what value its on, even if it isn't powered.

Incremental

An incremental encoder only keeps track of changes. It gives off signals if it is turned one way or another.