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joshuabardwell
Elite Member
By using relays you can design circuits that would take a very complcated switch to duplicate. One of my favorites is a circuit that won't let you switch off an engine while the lights are still turned on. Turn off the key and remove it, the engine still runs until you turn off the lights, at which time everything shuts down and won't restart without the key. On an old 4x4 I could push a button which would let the engine run without the key, but shut everything down as soon as anyone touched the brakes-great for leaving it running with the heater on while you went in for coffee in an area where someone else might try to drive away.
That's really clever. Having done some more research, I see that you can build, basically, logic arrays out of relays--using them like boolean gates and stuff. The simple examples I have been thinking of (turn on X when Y is turned on) really don't begin to tap the possibilities with relays.