This untuned circuit uses one of the world's first commercial transistors, the CK722, having been found in a 1966 publication. Equivalent modern types can be used.
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....