This circuit, which can be seen elsewhere on this website, was obtained from a 90’s English documentation. The circuit drives a small speaker, but for greater volume an external amplifier must be used.
The capacitors on this circuit determine the frequency that this circuit can detect. We can adapt...
This resistance meter with the CA3130 was found in an English publication from 1977. The circuit has...
This wide-range radiation monitor was found in a 1980s documentation. The circuit uses a diode as a...