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How do I wire these LEDs? Answered

I'm need to wire 4 blue LEDs (3.4v) and 2 ultra bright red LEDs (1.9v), I would like to limit the current to 10ma and wire all the LEDs to a single wallwart. The wallwart I was planning on using is 12v DC 100ma. I'm pretty new to LEDs so I'm not quite sure how to do this, I was thinking about wiring the 2 reds and 1 blue in series and wiring the other 3 blues together in series and then wiring the 2 sets together in parallel. But I'm not sure if that will work because I read somewhere that if you're wiring in parallel all the LEDs must have the same voltage. So if anyone could explain how I could wire this up (and maybe even draw up a simple diagram) that would be great.



10 years ago

I would put two blues and a red in each of two series strings (with a resistor), and put those two strings in parallel (which you can do because the resistor will "fix" things that way.)


Reply 10 years ago

PS - measure your 12V supply; if it's not regulated (which would be typical of a 100mA supply), it may put all significantly more than 12V at low loads...