Project Start Date: Dec 2005 Project End Date: Dec 2005 Current State: Completed
Leyden jars (aka High Voltage Capacitors, see the Wikipedia article) are an easy way to make high voltage capacitors, albeit with low capacitance. I wanted to make some for some high voltage experiments. I used clear beer bottles for the glass jars (which also serve as the dielectric), salt-water for the inside electrode, and aluminium tape wrapped around the bottle for the outside electrode. Stainless steel rod went through a cork in the top into the salt water to provide the electrical connection to the inner electrode.
I think I made about 12 of these capacitors. Unfortunately a bottle of sodium hydroxide sitting next to capacitors leaked a few days after I finished making them. The sodium hydroxide solution could be one of the worst possible things to get in contact with these capacitors and it ate both the aluminium foil and the glass, destroying every single one. I can't remember what the capacitance was and I never got to test them :-(.