We found this circuit in the September 1992 issue of Radio Electronics magazine. It can be triggered by any signal above ½ Vcc, where Vcc is the supply voltage.
This circuit takes advantage of the temperature variation of the component with the air flow that...
Found in an Electronic Engineering from the 80's, this circuit makes use of components of the...
This reflex receiver for the mid-wave range employs germanium transistors of the time. We found it in...