This circuit uses two relays that switch when the voltage exceeds the value given by zener D2. The circuit is from a Radio Electronics magazine from April 1975.
This circuit appeared in the June 1990 issue of Radio Electronics magazine. Integrated circuits must...
Lockout shooting, due to the incidence of light, can be achieved with the circuit in the figure. In...
This circuit can function either as a crystal or galena receiver with a pre-amplifier using a FET...