All rotary encoders consist of a light source, light detector, code wheel, and signal processor. There are two basic encoder styles: absolute and incremental.

Absolute encoders have an encoder disc which has marks or slots on a power-transmission shaft and a stationary pickup. The disc records a unique code for each shaft position.

For thoseknobs, you have the choice betweeneither a potentiometer boasting lowcost, high resolution, and absolutereadout but only limited travel—typicallyless than 340°—or a mechanical-opticalrotary ...

Oriental Motor of Japan is offering stepper motors with battery-free multi-turn absolute position encoding that can ride through power-loss. The encoder, ...