http://www.youtube.com/watch?v=o0hXYfvnND0 What would happen if the ground was kept in place and the positively charged rod was constantly moved to and away from the electroscope? Would we not have ac current between the earth and the electroscope? Replace The electroscope with a capacitor where one side is continuously charged and discharged and the other side goes to earth. Could be an interesting little circuit. Any comments?