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 QST circuit generates 4 frequency signals according to the crystals used. Transistors admit...
This countdown electromagnetic ring launcher was found in an Electronic Hobbyst Handbook from...
This TTL circuit was found in an American documentation from the 80s. The components are common in the...