We found this circuit in a 1966 documentation. The circuit is intended for a door opening system by the headlight of a car. The sensor is a photo-FET, an uncommon component today.
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...
This linear LED scale circuit was found in the February 1992 issue of Radio Electronics magazine. Note...
This amplifier stage without an output transformer was found in Radio Electronics magazine from...