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Colorado
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So I have an LED project that could potentially pull 11 Amps through an ON/OFF switch.  All the switches I'm finding are gigantic ones and I need something small and that's a DP3T.  So, rather than pushing that much current through the switch itself, what else can I do?  Space on the PCB is at a premium: it's only 18mm wide by 60mm long and there's a crapload already on it.

So I need some ideas.
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Need a decent relay. 
Solid State Relay
http://www.mpja.com/20A-480VDC-Solid-State-Relay/productinfo/17288%20RL/
Mechanical Relay
http://www.mpja.com/12VDC-DPDT-20A-Aromat-Relay/productinfo/18610%20RL/

http://www.mpja.com/Relays/departments/132/

Gonna need some hefty traces for that much current.
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Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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Colorado
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Gonna need some hefty traces for that much current.

Yeah, the entire underside of the PCB is the voltage rail.  The entire piece is only 29cm long with 48 RGB LEDs on one side.  Four of those pieces together pulling off of the same power supply ...  The wires connecting them to the power supply will have to be nice and hefty.

Thanks for the links, I'm gonna go do some studying.  Question: would it make any difference if I use one large relay, or two smaller ones in parallel?  So instead of looking for a single 12A one, use two 6A ones instead?
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Colorado
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Oh yeah, those relays won't fit on the PCB. smiley
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48RGB Modules*3 LED/Module*.02A/LED = 2.88A.
How'd you get 11A?
Relays in parallel, not a good idea. Use one to power some LEDs, a 2nd to power other LEDs.
Solve the current difference first tho.
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48RGB Modules*3 LED/Module*.02A/LED = 2.88A.
How'd you get 11A?

Re-read my message.  I said, four of them together.  And the LEDs are running at 18mA:
48 * (18mA * 3) = 2.592A  Multiply that by 4 pieces and you get 10.368A.  Add a little more the AVR and uSD card and I round it up to 11A for the whole piece.

Relays in parallel, not a good idea. Use one to power some LEDs, a 2nd to power other LEDs.
Solve the current difference first tho.
So I could potentially use four 3A ones, one for each section.  Tie them all onto the same ON/OFF switch ...
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Ok, next question: I'm looking at the Omron G3VM-21DR (http://goo.gl/NAW3I),  20V, 3A.  What is Rl used for and what's the difference between Vdd and Vout?
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