Electric Field Sensors

This scheme looks like a differential amplifier arrangement with common source. If two gates experience different electric potential with respect to identical source then the drain current will differ and can be measured easily. Assuming that the gates will be near zero potential with respect to source and difference in potential will be about 0.1V/mm separation of the gates, then it will cause a current difference of several microamps in the drain currents and that can be easily measured by ordinary microamp meter. Perhaps it will be a very good device for static electricity measurement. If you take high frequency devices then you should be able to pick up radio signals using the same device. Increasing and extending the gate reach to greater potential difference, much greater current change up to 10mA or even more can be observed.

I think it is a good way to sense electric filed and static potential. You have brought out a very good point for discussions. I am sure others will come in and will say more about it.