I want a cheap tool for investigating the source of and solutions for static electric shocks (from a vehicle).
This link shows a particularly attractive solution; just a FET, LED, resistor and battery.
I have some questions though.
- Will it work with both positive versus negative charges? If not, how could it be modified?
- How easily can the FET be damaged? Is there any way to protect it?
- How could the circuit be modified to give a better idea of the magnitude of the charge? (For the sake of vaguely determining the painfulness of the shock - voltage or amount of charge or both? I don't know). Simply measuring the drain/source current with a multimeter perhaps?
I don't know if it will be more useful to have the device detect charge at a distance, or by contact - perhaps the indication of magnitude would be most useful as it would enable both.