We found this circuit in the June 1992 issue of Radio Electronics magazine. The sensor is a common diode. The circuit is powered by the power grid from a 12 V transformer.
This SCS counter circuit was found in a 1964 General Electric documentation. The circuit has a...
This simple 1-transistor reflex receiver was published in Radio Electronics magazine in September 1959....
Operational amplifiers used in this 80's circuit is not very common today, but the setting can be...