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.
Also suitable for use as a noisy alarm, this Morse Code or telegraph practice oscillator was found...
This circuit makes simultaneous control of two up to 150 W incandescent lamps. The circuit is half wave...
This circuit was found in an old documentation from Europe. The integrated circuit used is...