SETUP
PARTS:
1 - Standard 9-volt battery
1 - MPF-102 N-channel Field Effect Transistor (FET) Radio Shack #276-2062 (May no longer be available if so search eBay for MPF-102)
1 - Red Light Emitting Diode (LED) Radio Shack #276-041 (You can pick other colors if you want)
1 – 1 Mega ohm resistor Radio Shack # 271-1134
As an option, you can get a 9volt batter clip to make it easier to build, but overall, it should be less than $10 at Radio Shack for the parts. If you’re going to build more than one, I suggest sourcing the parts off eBay to save on the costs.
Building the electroscope is pretty easy.
Just hook up the components as shown in Figure 1.