current source variations from 4QD, SBS and PUT with discretes

Current sources

4QD-TEC shows many variations
http://www.4qdtec.com/csm.html

PUT and SBS silicon bilateral switch, discrete
http://www.4qdtec.com/putpr.html#efld

application:

Electric Field and Leakage Detector

And now for something totally different. It detects very small currents such as those caused by leakage and changing electric fields.