We found this sensitive high input impedance voltage amplifier in the November 1970 Radio Electronics magazine. The circuit is powered by 18 V power source.
This circuit provides a signal when dialing occurs. The circuit is powered by the telephone line...
Using the RCA CA3018 integrated circuit, this amplifier was found in an article in the August 1970...
This circuit was obtained from Radio Electronics magazine in May 1958. The circuit uses...