Control devices are used to "turn on" or "turn off" current flow in an electrical circuit. Control devices include a variety of switches, relays, and solenoids. Electronic control devices include capacitors, diodes, and transistors, but those will be discussed in another training module.
Control devices are needed to start, stop, or redirect current flow in an electrical circuit. Most switches require physical movement for operation while relays and solenoids are operated with electromagnetism.