How to: drive common cathode led with Arduino?

Using Arduino General Electronics
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I would like to make my own current driver, one for each led following your schematic Paul__B :slight_smile:
I've "calculated" a fitting power supply to be 19V 6*350mA=2.1. This means I'll use a laptop power supply at 19v, 4.5A. If I send 19V in to the current led driver, would I get 19V out in the led-pcbs or how do I control that?

But what about the values in the schematic, what is the easiest way to calculate those?

  • Is it possible to use the BC337 NPN transistor in the making, I've got that on hand already. Which power transistor/Mosfet would be suitable? :slight_smile:

Best regards
Joe