How-To-Wire-It.com, Galco.com and 1728.org are some websites offering basic relay switch diagrams. The types of switches diagrammed include electromechanical, solid state, solenoid and single-pole double throw relays.
How-To-Wire-It.com provides diagrams for a square 3-pole relay and a round 2-pole relay. The site includes detailed instructions and a switch terminology page for relay switches needing more contact arrangements.
Galco.com offers diagrams for electromechanical relays and solid state relays. Electromechanical relays use magnetic force to open and close contacts. Solid state relays, which have no contacts, use electronic switching.
The 1728 Software Systems website offers diagrams of solenoid and single-pole double throw relays. The site also includes diagrams for automobile starter circuit relay switches and burglar alarm relay switches. Each diagram is accompanied by detailed instructions.