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.
Two 3-terminal regulators like the LM317 can be used to "clip" a sinusoidal signal, in order to...
This 7400 TTL circuit has a memory, keeping the LED on when a pulse is detected. The circuit must be...
This sole beacon which has a battery charged by photocells was found in documentation from 1991....