We found this circuit in a Radio Electronics from December 1963. The circuit combines valves and transistors and has a high input resistance. The circuit is powered by two batteries.
The recommended distance between the emitter and the phototransistor is 10 mm for this...
The input and output frequencies of this circuit depend on the coils and capacitors of the tuned...
This circuit was obtained in a 1991 publication. What it does is to amplify a signal with unit...