Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a 12V relay. The circuit can be implemented with modern equivalent components.
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...