This circuit is from a 1966 NASA documentation. The circuit uses a photodiode as a sensor. The other components are from that time.
This 1980s circuit uses components of the era that can be replaced by modern equivalents. For the FET we can...
Delivering Over 4X More Battery Life and Faster Time to Market, Platform Comes Complete with...
This is a traditional version of electroscope with FET. We found it at Popular Electronics. The...