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Article #5069Re: Electonic scales question...
From: Charles Keith
Date: Fri, 13 Jul 1990 21:11
Date: Fri, 13 Jul 1990 21:11
37 lines
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2464 bytes
In article <25815@unix.cis.pitt.edu>, fmgst@unix.cis.pitt.edu (Filip M Gieszczykiewicz) writes:
questions:
>
> of coils with a movable "plunger" that moves depending
> on the weight of something. (I presume it's cheaper)
>
> How does it work?
>
> 3) There is an adjustment pot for the end-user (on the
> fron panel) and another one on the pc board that's not
> accessible so easily, what is it for?
>
Thousands will tell you that this scale probably uses an lvdt (linear
variable differential transformer) for sensing the position of the core.
The springs in the scale make the cores position proportional to weight.
I am following up because I have an interesting story from many years ago
when these scales first came out. A friend of mine told me about another
friend who really liked to drink beer, so much so that he kept a keg
in his refrigerator at all times. But he never knew when the darn thing
was going to run out (keeping track of how much he drunk was out of the
question). I suggested that he get one of these scales, move the display
to a convenient place, move the "on" microswitch to a convenient place,
and adjust the zero offset pot (the "user accessible" pot mentioned above) and
the scale would read out directly in pints remaining. Alternatively, the
second pot ("span" or "calibration") could be used to make it read out
glasses of any reasonable size. Simply push a button, get beer status.
I was told that the "Beer-O-Meter" was a smashing success, a true triumph
of modern technology, and a winner at any party. It was accurate down to
a couple of glasses remaining. Cheers!
->Charles(have you hugged your Beer-O-Meter today?) Keith
--
Charles Keith
Hewlett-Packard Co. UUCP: {hplabs|ucsd|hpfcla}!hp-sdd!charles
16399 W. Bernardo Dr. Internet: charles%hp-sdd@hplabs.HP.COM
San Diego, CA 92127 Disclaimer: I am not a qualified spokesperson.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!hp-sdd!charles From: charles@hpsdl216.sdd.hp.com (Charles Keith) Newsgroups: sci.electronics Subject: Re: Electonic scales question... Message-ID: <1990Jul13.211144.26529@sdd.hp.com> Date: 13 Jul 90 21:11:44 GMT References: <25815@unix.cis.pitt.edu> Sender: charles@sdd.hp.com (Charles Keith) Reply-To: charles@hpsdl216.sdd.hp.com (Charles Keith) Organization: Hewlett Packard, San Diego Division Lines: 37