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12V 50mA to 100mA trigger pulse reinforcement - HELP

ronnol

Dec 8, 2009
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Dec 8, 2009
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I was hoping someone might be able to help me figure out an issue I'm having with a 12v trigger. I have a NuVo Grand Concerto system and an older amp, without any 12v trigger, powering one of the zones. Thus I tried to add a Russound ACT-1 (voltage triggered AC outlet) to power on/off the amp with the 12v zone trigger from the NuVo. Problem is the NuVo outputs 12v@50ma and the Russound requires 12v@100ma to trigger. Thus it is not triggering the ACT-1. Taking a 12v 250ma power supply to the Russound triggers it fine and the 12v output of the NuVo triggers a new amp, with a 12v trigger, fine. I added a relay, IDEC RH1B-U DC12V, and you could see the coil trying to flip but the NuVo's 50ma was not enough to trip the relay. I saw some internet posts about using a transistor, diode, and resistor with the relay and power supply but I'm no electrical engineer to figure it out. Any suggestions? Thanks for the help.
 

Resqueline

Jul 31, 2009
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Jul 31, 2009
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I've never seen such systems before, but it seems to me the only thing you need is a transistor and a 15V (100mA) power supply to reinforce the trigger pulse.
Get a 2N2222, or just about any NPN transistor, connect its base to the NuVo output, the emitter to whatever you want to control, and the collector to +15V. The negative of the supply connects to negative or ground of the pulse wiring.
I don't see any need for a resistor or a diode here. Even if one often uses a diode across relay coils to protect the driver transistor, this one is configured as an emitter-follower and should protect itself.
 
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