two leds, one output?

Hi all,

I'm getting old :wink: I forgot the proper way, and the search of these words gives too much results. I want to drive two leds with one PWM output pin (left eye and right eye of my evil spider ]:)). Serial or parallel? (For the latter: one or two resistors?).

best regards
Andreas

If the forward voltage is low enough --> serial. If it is to high --> parallel with separate resistors.

Brett vorm Kopf (plank in front of head :)). Standard LED, U_F = 2.25 V; this gives the forward voltage of 4.5 V. So: 5 V - 4.5 V = 0.5 V; R = U/ I is here R = 0.5V / 10 mA = 50 Ohm. Is this correct? (Just to be sure).

Thanks, Danke, merci, gracie
Andreas

Is this correct?

Yes :slight_smile:

Thanks, Danke, merci, gracie Mike! I've done this stuff 40 years ago, so the knowledge got a little bit rusty :wink:

Andreas