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Topic: 12v common cathode LED strip help (Read 823 times) previous topic - next topic

ttyrawa

I am trying to control a strip of leds that run at 12v a share a ground.

At my use I have 3 TIP42 PNP Transistors. and two Darlington Driver 8-Channel ULN2803 DIP, as far as transistors go.

I thought I could get away with just using the pnp's to work the leds but it's not working. Can anyone recommend a schametic that will work? Does the arduino have to have the same ground as the LED or can I power the leds from a 12v source and the arduino from usb or some other power source?

sirbow2

you can use separate power supplies, but the GNDs do need to be shared. on the TIP42:

+12v -> E pin on TIP42
Arduino pin -> 270ohm ->base pin
C pin on TIP42 -> LOAD(the +12v pin on the LED strip) ->GND
http://dduino.blogspot.com all my Arduino/electronic projects!!!

{NEW} Getting Started, Learning, Reference + FAQ PDF!!:
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ttyrawa

Thank you for your input. Although it didn't work it did help me to a solution that does. I added some npn transistors infront of them and now it works!

sirbow2

you got me puzzled, what did you do with these NPNs?
http://dduino.blogspot.com all my Arduino/electronic projects!!!

{NEW} Getting Started, Learning, Reference + FAQ PDF!!:
[url]http://ar

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