Can this setup hurt the digital pin ?

Hello everyone,

I need to know if this setup can damage arduino digital pin:

This way the led will blink when the digital pin is set as LOW.

I know this is not the usual manner to blink a led. I have in here some numeric digital display that share the positive pole and you control the segments by hooking them to ground. So this is the type of setup I will need to use to use the display.

The display data sheet: A-503G-A is the model I'm using.

It's possible to use some ordinary shift register to control the display?

Appreciate any clue/suggestion.



I know this is not the usual manner to blink a led.

It isn't?

Have a look at the AVR's current source and sink capabilities.

Hello AWOL,

Maybe it is and Im just not awared. The way I knew to blink a led is by making it blink when digital pin is set as HIGH.

And thinking a little more about the scheme, the led is an diode so no drain when pin is set to HIGH.. I suppose. Didnt think about it lately. Im just returning to my amateur electronics after 1+ year... must put brain to work again.

Very thanks for the reference !


It's exactly how you power common anode LEDs. The AVR pins can source or sink a maximum (absolute - don't go near) of 40mA, up to a per-chip limit of about 200mA. Your 1kohm resistor will keep the current (and the brightness) down.