Found in documentation from the 1980s, this highly sensitive circuit is based on the conduction by the presence of gas from an ionization chamber. The components are from the time.
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...
This 1969 Mullar circuit appears elsewhere on this site. The circuit uses germanium diodes and the...
This control circuit for direct current motors uses a 741 and an operational one of unusual power...