Need some help with triggering an LED circuit

Thread Starter

outsider787

Joined Nov 11, 2011
3
I have an input signal which is either 3V or 0V.
From a battery I need to drive an LED with this signal.

I need the LED to be on when the signal is at 0V and I need the LED to be off when the signal is at 3V.

Anyone have any idea how I can wire this up?

Thanks,
adrian
 

Bernard

Joined Aug 7, 2008
5,650
A one transistor invertor should do for a red LED @ 20 mA. One k Ω base R, 50 +- Ω for LED current limiting. 2N3906 or similar.
 
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