Date: Wed Oct 8 12:10:05 2008

Author: J. Terrence Klopcic

Subject: Re: Current Balance

Post:

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Don,

We use an old set of Sargent-Welch-Cenco current balances. However,
there are two major drawbacks in the new sets:

1. Even without the plates for doing charge balance, the price is
$565. (You don't want the set of plates for doing charge balance. We
have found that to be a most frustrating - and physically wrong -
experiment and have developed a different charge balance experiment.)

2. The required current - 1020 Amps!!! - is prohibitive - hard to
generate and awfully hard to measure.

(http://www.sargentwelch.com/coulomb-and-current-balance-cenco/p/IG0038380/)

Fortunately, the old - and seemingly identical - sets that we use get by
on considerably less current. I guess that's inflation for you.

Terry


* J. Terrence Klopcic, PhD
Director of Laboratories
Departments of Physics and Mathematics
Kenyon College*



DMathies@tulsacc.edu wrote:
>
> I need information on a good Current Balance for use in second
> semester calculus based physics courses. Must be less than $500 each
> set up and of course I need the info very soon or will lose the funds.
>
> Has anyone experience with the Pasco Current Balance? Thoughts?
>
> Don Mathieson
> Tulsa Community College
> dmathies@tulsacc.edu

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Don,

We use an old set of Sargent-Welch-Cenco current balances. However,
there are two major drawbacks in the new sets:

1. Even without the plates for doing charge balance, the price is
$565. (You don't want the set of plates for doing charge balance. We
have found that to be a most frustrating - and physically wrong -
experiment and have developed a different charge balance experiment.)

2. The required current - 1020 Amps!!! - is prohibitive - hard to
generate and awfully hard to measure.

(http://www.sargentwelch.com/coulomb-and-current-balance-cenco/p/IG0038380/)

Fortunately, the old - and seemingly identical - sets that we use get
by on considerably less current. I guess that's inflation for you.

Terry





J. Terrence Klopcic, PhD

Director of Laboratories

Departments of Physics and Mathematics

Kenyon College




DMathies@tulsacc.edu wrote:

I need information on a good Current
Balance for use in second semester calculus based physics courses. Must
be less than $500 each set up and of course I need the info very soon
or
will lose the funds.


Has anyone experience with the Pasco
Current Balance? Thoughts?


Don Mathieson
Tulsa Community College
dmathies@tulsacc.edu





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