Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It can be replaced with LED with appropriate series resistor. Transistors may be modern equivalents.
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...