General Purpose Relays
Relays are electromechanical devices. Power/Signal Relays, Reed Relays, RF Relays, Special Relays, and Time Delay Relays, are relays. A relay is an electrically controlled switch which uses current to create a magnetic field to attract an armature which is used to mechanically operate a switch. Solid state relays are relays which control power circuits without using any moving parts.