This alarm circuit was found in April 1975 Radio Electronics magazine. The circuit uses a 12 V power supply and relay but can be modified to work with other voltages.
This circuit in a receiver that allows the capture of distant stations with short waves. The...
This experimental receiver was found in an English publication in 1979. It can receive medium-wave...
This circuit was found in an Italian publication in 1975. The transistor must have a heat...