I buolt a cute circuit with a 2n7000 from an idea I saw at the Maker
Faire.. It is an E field probe: you can light up (or extinguish,
depending on your charge polarity) an LED with the proximity of your
finger from half a foot.
It can be very instructive in seeing where you have static, and how far
away the 2N7000 can tell, and (eventually) what will and won't blow
it.
I put a link to this, and a copy of Wayne N6KR's note on handling the
2N7000, onto Wikipedia.
http://en.wikipedia.org/wiki/2N7000
Leigh/WA5ZNU
On Tue, 14 Aug 2007 8:57 am, Ron D'Eau Claire wrote:
Perhaps it deserves saying the obvious: DO NOT USE FOAM CONTAINERS FOR
ELECTRONIC PARTS!! (Unless, perhaps, you're working with vacuum tubes
<G>)
Expanded foam in any form is a wonderful static generator. It doesn't
take
enough static to see or feel a spark to destroy parts, only enough to
exceed
the part's operating voltages (especially insulation breakdown
voltage).
That is often well below that at which a human is even aware there is a
static charge present.
I suppose one might argue that keeping the leads of sensitive parts
stuck in
the conductive foam protects them, but I tend to be conservative. It's
bad
enough troubleshooting to find a defective part when power is first
applied,
but static-damaged parts sometimes still work, somewhat, so the rig
just
doesn't meet normal specs and the operator may be completely unaware of
it.
And then the part may fail prematurely at some later date (just as
you're
calling that rare DX you need or about to start a contest session).
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