This circuit is from an American documentation from the 90s. The transistors are of power and must be equipped with good heat sinks as well as the integrated voltage regulator.
This circuit was obtained in an old American publication from 1978. It can be assembled with a...
Decade counters, such as the 4017, can be cascaded as sourcing signals with the frequency divided...
This circuit uses a dual-gate MOSFET, a rare component today. We found it in American...