This simple 12 V power supply with current up to 2 A was found in a Popular Electronics from the 90s. The zener diode is 14 V and transistor Q2 can be a TIP42.
This circuit, from a publication in the 1970s, uses transistors that no longer exist, but can be...
Indicated as a joke or challenge this circuit shows how it is possible to control two lamps using...
Found in a 1960s RCA documentation, this circuit applies to most common triacs. The trigger device is a...