## PSN-L Email List Message

Subject: Re: force gauge/transducer
From: ChrisAtUpw@.......
Date: Tue, 31 Jan 2006 16:47:00 EST

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In a message dated 30/01/2006, JDarwin@............. writes:

Anyone  know of a simple... quick... force gauge or force transducer...
20 - 30  grams max with a resolution of .1 gram.   that I could make or  buy?

I'm working on a wind tunnel for my grandson's science fair  project and
we need a way to measure the lift and drag.
I  can  measure lift with a beam balance scale..

Oh... and did I say  cheap?

Hi Jan,

You can buy 1 mm thick sheets of a rubbery  like material called QTC -
Quantum Tunneling Composite. You sandwich it between  two metal plates and
measure the resistance between them. With zero force you  have a near insulator. As
the force increases, the electrical resistance drops.  This is a cheap way of
making a force transducer.

Regards,

Chris Chapman

In a message dated 30/01/2006, JDarwin@............. writes:
<=
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style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Anyone=20
know of a simple... quick... force gauge or force transducer...20 - 30=
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grams max with a resolution of .1 gram.   that I could make or=20
buy?I'm working on a wind tunnel for my grandson's science fair=20
project and we need a way to measure the lift and drag.I  can=
=20
measure lift with a beam balance scale..Oh... and did I say=20
cheap?

Hi Jan,

You can buy 1 mm thick sheets of a rubbery=
=20
like material called QTC - Quantum Tunneling Composite. You sandwich it betw=
een=20
two metal plates and measure the resistance between them. With zero force yo=
u=20
have a near insulator. As the force increases, the electrical resistance dro=
ps.=20
This is a cheap way of making a force transducer.

Regards,

Chris Chapman
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