YHDC current sensor - the theory please

[flotulopex]

Oh, I get it now, the "plotter".

I just need to monitor a current level that will trigger a relay.

I do have ACS712 but the problem is, the current has to pass inside (though) the component meaning I would need to modify the cabling inside an electric board where it is intended to be installed. But I want to avoid this - it has to be like SHELLY energy counters or so.

I just received a module, an analog AC Current Sensor SEN0211 unsing a YHDC current transformer: DFROBOT. I'll give it a try.