This circuit uses a transistor to trigger the alarm from a low quiescent current sensor. The relay is 12 V. The circuit is from Radio Electronics magazine, April 1975.
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...