@skywatch great, thanks a lot for your suggestion. A bit of research on the internet educated me about these diodes looks like they already exist on the board that carries the relay. However, i deeply thank you for the info. This forum and internet in general is such a powerful tool
@ejlane your concern is fully justified i also come from an engineering background and i like to think "worse case scenario".
The more one look the more one find that the very vast majority or microwave ovens work the same way : there are 3 industrial switches built in the door lock. 2 of them are cabled on the "power side", one is for signaling ("software side"). So we are pretty safe on that matter.
But you are so right about safety. Magnetron do emitt dangerous waves and capacitors and stuff packed in the oven can be deadly because of high voltage.
Thanks both for suggestions. I will come back with updated sketches and beg for advice once more
I would like to step up 3.3V from my power supply with the help of a dc-dc-boost converter to 5V and then I want to draw 500mA by placing a 10 Ohm resistor between the output-pin of the boost-converter and ground.