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.
This circuit for 40 V systems was found in a Linear Technology application manual. The circuit...
This circuit was obtained in a 90s Popular Electronics. In the table the values of the components...
This transmitter for the 7 MHz range, as we can assume by the number of turns of the coil, since the...