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.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...