base on the bedini‘s version,except i Modify the 555 time output frequency to 60hz-120hz,and the test frequency is about 60hz。and the spark gap is made by the Silver piece,output resistance is 4.7K(bedini ‘s diagram is 4.6K),when i use the electrode contact my hands ,i can feel a little electric shock。so the 4.7k should be adjust to a larger value。