Forums normally do not like it when a poster is directed to another web page. Unfortunately I do not know how to make a link nor how to post an attachment so if I am transgressing please forgive me Pebe.
There are some circuit diagrams of Dr Robert Beck to be found at www.sharinghealth.com
At the bottom of the page there is a heading "PDF articles" below it are some headings that you can click on. One of them is the circuit diagram of the equipment you wish to build.
It is an oscillator - square wave - running at 4 Hz with three 9 Volt batteries in series to give the 27 Volts output.