24VDC and 5VDC to the same 0V

So I am trying to use an atmega328 and the arduino software to control some 24v industrial equipment with relays. I have a 24VDC power supply that I'm converting down to 5VDC for the ATMEGA328 and associated parts. For the sake of ease I have the 0v end of all components, 24V and 5V, going to the same 0V line. Is this right? Or am I going to blow myself up?

That is right. The entire circuit will need the same reference point for GND so usually you would connect all the grounds together. No puppies should be harmed :slight_smile:

Geoff

In such a setup, where the ground is shared with a higher voltage power source, could there be any problem if there were any negative feedback?

RudiAhlers:
In such a setup, where the ground is shared with a higher voltage power source, could there be any problem if there were any negative feedback?

Could you define what you mean by 'negative feedback' in context of using multiple DC power supplies. There is a requirement for all voltage sources to share a common ground unless you are using some form of opto-isolators to interface the higher voltage components.

Lefty