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Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I agree with adding gate-source resistors, start with the highest value that you can find, e.g. 33 MOhm. Lower resistance = greater stability Higher resistance = greater sensitivity
Don't make it too stable or it will not detect the smaller ghosts or higher flying UFOs .
P.S. gate-ground is more common and useful than gate-source, as it allows more stable source-ground voltage - hence stable bias, assuming that you are using a source resistor, if you do not use a source resistor (typ 100R to 1kR) the drain current will drift a lot with temperature..
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
I can't see your vid, but I was working on this years ago and the main problem I had was the gates stayed charged too.
I think I got around this by using a square wave to power the JFET, I say that because I never committed to a design, but give that a try too and see if that will work, I can't remember if it did.
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Static electricity detector
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