Suggested by Mullard in an old documentation, this circuit is based on a common phototransistor and on transistors that may be the modern BC548.
This is a commercial circuit from the year 1958. Transistors are germanium types and transformers...
This simple circuit with LDR was found in the Radio Electronics magazine of July 1992. Any...
This circuit converts signals from the longwave band of 350 kHz to 500 kHz to 4.35 to 5MHz. The...