This circuit was originally intended for reading movie soundtracks. The circuit is from 1967 and was found in an English publication. The sensor is semiconductor type.
Found in a 1969’s Electronic Design, this circuit operates in a narrow range of voltages....
This power stage with two counterphase transistors and coupling transformers was shown in Radio...
Found in old documentation, this circuit uses special discharge lamps (neon) of the time. The...