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 circuit was found in an American publication from 1969. Transistors are from the time and can be...
We found this circuit in a 1998 documentation. The circuit makes use of CMOS logic and must be...
This 1 transistor circuit is from a Radio Electronics from December 1958… The circuit is battery...