I’m building a mains sensor that should be able to operate safely at a voltage of up to 650VAC. I’ve already built one before, that operated with 130VAC, which I successfully monitored with a MCU, and printing the results onto the serial monitor on my laptop. Later I built it on a PCB with copper dots, same schematic, but this time I connected it to my dads computer, and guess what, it blew up. But it worked on my laptop (although it was a breadboard version), which is because the laptop is battery powered, right? I UNDERSTAND THAT EXTREME CARE SHOULD BE TAKEN WHILE DEALING WITH SUCH HIGH POWER/VOLTAGE. AND THAT IT CAUSE SERIOUS BURNS AND DEATH! I KNOW IT SOUNDS LIKE I DID NOT TAKE CARE WHEN THE COMPUTER BURNED, BUT IT WAS MY LACK OF KNOWLEDGE. I AM WILLING TO ACCEPT ANY ADVICE YOU GIVE ME. SECURITY IS PRIORITY. I used a bridge rectifier capable of 800VAC 1A. The capacitor is electrolytic 1000uF 16V. The resistors are 2W (I use 4, schematic shows only 2 for simplification) and values are chosen to get specific voltage. So do I only need a Zener Diode or do I need more? Optocouplers?
Edit I want to use this sensing to monitor the voltage and if it goes under the preset value of a pot, it should cut the supply to the device or motor that is connected. Any positive advice is greatly appreciated!😃