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 circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs...