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I need some kind of switch . . . I think

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MonMotha:
A relay really isn't the way to go here, especially if you want to flash things on and off a lot.  Relays have limited lifespan due to being mechanical, and they're noisy.  I kinda addressed this above.

Relays are good when you need to switch AC line voltages and reasonably high currents at slow rates of speed, but in this case, a transistor (either bipolar or a MOSFET) is the way to go in my opinion.  They are solid state (no moving parts to wear out), and they aren't much harder to wire up than a relay.  Depending on the transistor you choose, you may have to adjust the base resistor a bit (grab some 100 ohm and some 47 ohm too, in case).  A relay would still require a diode to provide protection against the inductive kickback at turn-off, so it's not exactly a single part solution, either.  As a bonus, transistors are generally cheaper than relays.  Not to mention that some relays need more than 20mA of coil current!

Most arcade games that turn small DC lamps on and off use low side NPN transistor switching, sometimes using arrays built into a single chip if they need several.

Radio Shack sells some of the TIP series, which would be fine for this application (if overspec'd).  The TIP31 is an NPN and the TIP42 is a PNP that Radio Shack sells.  You can use smaller transistors, too: the classic 2N2222 or 2N4401 would also work fine for low side switching.  These come in smaller cases and may be a little more difficult for you to wire up, though.

polaris:
cheers dude i wasnt disagreeing i was kinda asking for confirmation on what someone else had told me, and it looks like they steered me wrong :cheers: 

MonMotha:
I didn't mean to imply that you were.  I just wanted to make my rationale behind rejecting the use of a relay clear since the topic was brought up further (I only glossed upon it earlier).

polaris:
its all good mate , i probably gained more from this thread than the poster :cheers:

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