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[quote]QUOTE: Originally posted by elkman Being electronically challenged, I need help. I have a 9 vdc Radio Shack mini relay for a background sound project. Does anyone have a basic diagram on how to wire a relay?? It has 5 prongs--1 common, 1 NO, 1 NC, and 2 for coil. I cannot figure out what goes where. Thanks. [/quote] elkman, Sounds like you have a SPDT (Single Pole Double Throw) relay. 1) To energize the coil and throw the switch (relay), connect DC power to the 2 coil connections (the electro-magnet). Polarity shouldn't matter. The other three connections are for the circuit you want the relay to control. (This circuit is independant of the coil and may be AC or DC and of a different voltage and/or amperage than the coil): 2) If the coil is not energized, an internal spring in the relay will keep the switch set for the NC (Normally Closed) path. This will be between the common connection and the NC connection. 3) If the coil is energized, the electromagnet created by the electrical current running through the coil will overcome the internal spring and throw the switch (relay) to the NO (Normally Open) path. This will be between the common connection and the NO connection. When the coil is de-energized, the internal spring will return the switch (relay) to the NC path. If your unsure, you can always use a battery and a small low-voltage lightbulb to the relay to see which connections you have a circuit for, and which you do not. Then energize the coil and test again, de-energize the coil and test again. The bulb will light whenever you have a circuit through the relay. Hope this helps. Dale B.
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