Using the CA3140 in the figure we have a comparator that goes low in the window voltage space. The circuit was found in June 1986 Radio Electronics magazine.
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...