Circuit Break

Apr 19, 2006 6 Replies
P

i have used a solid state DC DC relay for switch on and off my cars light. as usually the light remain off and when given the command to relay it completes the circuit and the light is on.



now i want to reverse the situation .. the light should remain on always (as soon the ignition of the car is switch on) and i can swicth the light off ..and on it again according to my desire.



how i can do it. will the relay i used work.? or i have to use any thing more. what will be the circuit diagrame for this type off cooncetion.



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E

+12-----------------------------+ | | / ----- | Accessory +----o o---| SSR |---+ Gnd ------------------| |------Headlamp---Ground -----

Connect the control side of the ssr to the accessory circuit in the car, through a switch.

Ed

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R

Then he will have lost the ability to turn the lights off, but that can be fixed with an SPST switch in series with the Accessory+ and the ignition switch to the input of the SSR.

Cheers! Rich

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P

Ed,

i had tried what you are saying .. but after there the light remain on always ..i loose the control of it ..i cant not switch it off ..while i want to switch it off at my command.

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E

Huh? I'm missing something. I already said that, and drew that. What am I missing?

Ed

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E

Ok - your SSR must have SCR output instead of Mosfet output. If that is the case, you need a different switching device. Go to a heavy duty automotive relay like RLY-351 for $2.40 from Allelectronics

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Wire the coil with a switch between the accesory voltage and the relay coil like this:

+12 | o--- ^---[Headlamp]---Gnd / -- Accessory +----o o---| /| Gnd ------------------|/ | -- RLY-351

You could change the SSR to one with Mosfet output, but that's expensive and offers no advantage over the regular relay in this circuit.

Ed

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R

OOpps! My bad! I misread your diagram, not realizing that "Accessory" was already switched. (I had ass-u-me-d that the switch you showed was the "Accessory" switch itself.)

Thanks! Rich

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