RE: JFET Static Charge Detector

genebren — Sun, 22 Aug 2021 23:15:08 GMT

Great experiment and blog! It was an informative and interesting experiment.

RE: JFET Static Charge Detector

jc2048 — Sun, 22 Aug 2021 22:00:59 GMT

Good experiment and demonstration.

The drain to source current flow is highest when the gate to source voltage differential is zero.

Although this is obviously nit-picking, I think you'd find, if you tried it, that it would keep increasing as you went above zero. Obviously, at some point, the gate-source diode is going to start to become forward-biased and spoil things by conducting, but you'd probably have a small amount of leeway before that happened.

In the detector circuit, the gate/antenna becomes negative relative to the source...

That's a bit vague. How does it become negative? Are you claiming that the statically-charged object adds negative charge to the gate/antenna? An alternative hypothesis might be that it causes a redistribution of the free electrons in the wire, so that there's a greater concentration down the gate end.

RE: JFET Static Charge Detector

shabaz — Sun, 22 Aug 2021 10:44:10 GMT

Hi Frank,

Awesome results! It's definitely a fun experiment too. Great diagram too by the way!!