This circuit was found in an American documentation from 1970. We can increase the number of multiplier steps to have higher output voltage. The operating frequency is around 1.35 kHz.
This different configuration for a crystal galena radio or modernized since a diode is used, has a...
This circuit is from 1990 documentation. When we press D1 the lamp remains on for a time interval that...
This version of the test lights a lamp when the ring touches the tortuous wire. The SCR can be the...