Found in a 1964 CQ magazine this circuit consists of an automatic telegraphic key, providing the correct duration for points and dashes. The circuit can be made with a current PNP transistor.
The presented circuit uses an uncommon operational amplifier but can be implemented with a more...
The circuit shown uses a FET as a stabilizer, as this type of circuit usually uses lamps in this...
This circuit is from an American publication from 1975 and can use other operational amplifiers and...