Alt-BEAM Archive

Message #05811



To: beam@sgiblab.sgi.com
From: "Sathe Dilip" sathe_dilip@bah.com
Date: Fri, 20 Aug 1999 13:48:26 -0400
Subject: [alt-beam] Re: Anybody recognise this manufacturer?


The picture is too blurred but from what I can see & the description
provided, that (manufacturer) will be Siliconix.

Dilip

> Richard Caudle wrote:
>
> Attached is a pic(blurry) of the 2N7000 that I'm using for my e-field
> sensor. The logo looks like an upper case 'S' with a lower case 'i'
> inside the 'S'. Any help would be appreciated.
>
> Name: 2n7000A.jpg
> 2n7000A.jpg Type: JPEG Image (image/jpeg)
> Encoding: base64

--
Pl. remove *s from the e-mail address to reply



5812 Thu, 19 Aug 1999 17:46:23 +1000 MOSFET sensor thingy BEAM = Richard Caudle =

---------------------------------------------------------------------------=
---


Evening all,

Yet another in a long line of strange things...

Today at work, I came across a circuit for detecting electrostatic fields=
. Since I have need for such a thing, I tried to build one. The only prob=
lem is that the required components weren't available (what else is new?). =
It called for an n-channel FET and all I could come up with was an n-chann=
el MOSFET (2N7000). I got the pinout from Digi-Key and proceeded to build =
the circuit. =


Needless to say, it didn't work. So I decided that the pinout must be wr=
ong. I turned it 180 degrees and it started working, but not like the desc=
ription said it would. The closer I moved my hand to the 'antenna', the hi=
gher the voltage went. I put in an LED so I could watch it. It was sittin=
g at about 530mV until my hand got about 10" away and it began to rise. At=
about 4 inches, it went to about 1.3V and when I would touch it, it jumped=
to 4.8V (input V=3D5VDC). =

=

The strange thing about it: The 2N7000 is backwards! At least I think i=
t is. The S (source?) pin is on the negative side of the supply and the D =
(drain?) pin is on the positive side. The gate is acting as the antenna. =
Maybe I've got the terms wrong. It's still a cool thing. I was thinking i=
t could be used as a 'real' antenna for a walker or popper. It could trigg=
er a Nu that operates the reverser. Something that deserves further invest=
igation(IMHO).

Richard Caudle
richard@cqc.com
Home ICQ - Frankendaddy

---------------------------------------------------------------------------=
---

Guardians of the sacred words: Nee, Ptang, and NeeWhon! =



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>
http://w=">http://www.geocities.com/TimesSquare/Cavern/9282/home.htm">http://w=
ww.geocities.com/TimesSquare/Cavern/9282/home.htm

style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0p=
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----- Original Message -----


style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">Fro=
m: =

Richard Caudle=
 =


To: i.com" =

title=3Dbeam@corp.sgi.com>BEAM

Sent: Tuesday, August 17, 1999 8:5=
7 =

AM

Subject: MOSFET sensor thingy >





 

Evening all,

 

Yet another in a long line of =
strange =

things...

 

Today at work, I came across a=
circuit =

for detecting electrostatic fields.  Since I have need for such a th=
ing, =

I tried to build one.  The only problem is that the required compone=
nts =

weren't available (what else is new?).  It called for an n-channel F=
ET =

and all I could come up with was an n-channel MOSFET (2N7000).  I go=
t the =

pinout from Digi-Key and proceeded to build the circuit.  IV>
 

Needless to say, it didn't wor=
k.  =

So I decided that the pinout must be wrong.  I turned it 180 degrees=
and =

it started working, but not like the description said it would.  The=
=

closer I moved my hand to the 'antenna', the higher the voltage went.&nbs=
p; I =

put in an LED so I could watch it.  It was sitting at about 530mV un=
til =

my hand got about 10" away and it began to rise.  At about 4 inches,=
it =

went to about 1.3V and when I would touch it, it jumped to 4.8V (input =

V=3D5VDC). 

    V>
The strange thing about it:&nb=
sp; The =

2N7000 is backwards!  At least I think it is.  The S (source?) =
pin =

is on the negative side of the supply and the D (drain?) pin is on the =

positive side.  The gate is acting as the antenna.  Maybe I've =
got =

the terms wrong.  It's still a cool thing.  I was thinking it c=
ould =

be used as a 'real' antenna for a walker or popper.  It could trigge=
r a =

Nu that operates the reverser.  Something that deserves further =

investigation(IMHO).

 

Richard Caudle

href=3D"mailto:richard@cqc.com">richard@cqc.com
Home ICQ - =

Frankendaddy




Guardians of the sacred words:=
Nee, =

Ptang, and NeeWhon!         =





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