Electrical – touch resistor connected to mains power?


Can I touch resistor connected to mains power?


simulate this circuit – Schematic created using CircuitLab

Best Answer

Of course you can.

Of course, a certain percentage of the times you do that you will die, but that's not what you asked.

Your circuit, as shown, is guaranteed to kill the LED, since on the negative halves of the power cycle as much as 310 volts will appear across the LED and destroy it. If you are lucky, the LED will fail short, and this will protect you. Murphy's Law ("Anything which can go wrong, will.") suggests that the LED will instead fail open, so touching your point will apply 220 volts to you. Of course, the 100k resistor will limit that current, but the result will still not be good.

As KH has answered, at your stage of knowledge, you should make an ironclad rule NEVER to deal with mains voltages directly. You simply don't know enough to deal with the hazards in a safe manner. Know your limitations.