Rotary potentiometers consist of a circular conductive track and an electrical wiper attached to a central shaft. A constant voltage is applied to the track; as the shaft turns and the wiper contacts ...

Linear potentiometers are constructed similarly to rotary types, except that their resistive elements are strips and the terminals are arranged in a linear fashion, as seen in the image below. Image ...

After becoming frustrated with drift in the potentiometers, he set out to outfit the entire rig with custom-built encoders. [s-ol] designed the rotary-encoder based boards around an FPGA.