This circuit was found in the May 1959 Radio Electronics magazine. Its purpose is to provide bias voltages for circuits under test. The circuit is isolated from the power grid.
It can be obtained from Mouser Electronics new superFETs III from Fairchild for voltages of 700 V...
This circuit was found in a 1969s American documentation. With modern components, it can be used...
The figure shows how to change the frequency of a 5 V LED blinking. The capacitor can have other...