[sdiy] LED current source needed for 'digital' outputs?

[Justin Owen]

Hello, just a little double-check here...

For an LED displaying a changing or AC signal I would always use some sort of transistor current source.

For an LED displaying a simple on/off digital signal - e.g. a logic output - is there any reason to not just use: Source > LED > R > GND?

This is a circuit being used in a modular environment so it will need to play nice with its neighbours and optimal/'reasonably' low current draw is a normal priority.

Thanks,

- J