Found in a Westinghouse Silicon Power Handbook from the 60s, this circuit makes use of period components. Special high voltage transistors are used. Zeners are 15 V.
This circuit, which can be used as a shield, was found in American documentation from the 1970s....
This circuit for low frequency data transmission was found in the May 1977 issue of Radio...
This circuit activates a relay that has a lamp as a load. The circuit is from a Radio Electronics from...