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.
This circuit was obtained from Radio Electronics magazine in May 1958. The circuit uses...
This circuit was obtained from the 1995 Encyclopedia of Electronic Circuits Volume 5. The circuit...
This tunnel diode oscillator was found in July 1986, Radio Electronics magazine. Note the low...