This wide-range radiation monitor was found in a 1980s documentation. The circuit uses a diode as a sensor and is quite critical requiring shielding shown in dashes to prevent snoring due to gain.
This configuration appears elsewhere on this site. It uses the LM101, which are not common today,...
The purpose of this circuit is only to increase the input resistance of a multimeter, since there...
When this circuit picks up a louder sound it produces a pulse that briefly charges the 10 uF...