Will this simple circuit work and is it dangerous? (See picture)


Joined Jan 27, 2019
The safety of the circuit is entirely dependent on the safety (isolation, etc.) of the power supply doing the 220 to 5V conversion, and incidentally the safeguards in the heating device to prevent overheating by misoperation.

Deleted member 115935

Joined Dec 31, 1969
Will it work ?
basically , no reason why not, provided the micro is not switched off by the relay.

Is it safe ?
May be, That is voltage and current that can kill you ,
so it depends on how you build it and specify the high voltage parts .