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LED dimmer PCB needed!? Answered

I was looking to make a LED dimmer cct and wanted to know if anyone had a pcb layout for one? The problem I am having is the 555 IC can only power 4 LEDs and i need to power 11 rows of 5.
I was woking off this cct
Can anyone help, thanks. 

4 Replies

steveastroukBest Answer (author)2012-05-01

There's no current limit resistor for the LEDs in that circuit, and it will need them. Make T1 into a darlington, like a TIP32 or something similar.

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crazyaxemax (author)steveastrouk2012-05-02

Thanks yeah i'm using a 560 ohm resistor sorry i missed that out. I didn't know darlingtons were so easy to make. Thanks for the help :)

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steveastrouk (author)crazyaxemax2012-05-02

Oh yeah, and connect the LEDs in the COLLECTOR side of the transistor, and connect the emitter to ground.

You don't have to run the LEDs on the same supply as the 555 either.
Every row will need its own resistor too.

Don't forget the Best Answer.


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mpilchfamily (author)2012-05-02

You can run more then 4 LEDs as long as the timer can handle the current. Just a matter of wiring them up in a series/parallel configuration. Unless your wanting the LEDs to all fade at different intervals.

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