We found this circuit in the October 1996 Electronics Now magazine. The circuit uses LDRs as sensors and drives relays. The relays must have voltages according to the power supply.
The circuit shown was found in the 1994 National Semiconductor's Linear Application Handbook. The...
This circuit was obtained in a 1965 American magazine translation. The coil is formed by 40 + 40...
This useful signal injector using two transistor was found in a Radio Electronics Magazine from...