[Phys-L] Re: Lab DMM Recommendations?

[Bernard Cleyet <anngeorg@PACBELL.NET>]

Mike has certainly thought about this more than I have!

Amazing how many list topics concern money and how to use it
efficiently.  Included in the tuition at some schools is a laptop while
so many others even w/ rising tuition can't afford basic necessary lab.
instruments.

I had imagined the students making up shunts from wire salvaged from
heaters.  I forgot the majority of students are not future Physicists.

bc



Edmiston, Mike wrote:

> Two comments...
>
> * * * Concerning students buying meters
>
> We do not have a lab fee.  Being a small university, and competing for
> students not only with other universities, but even with other
> departments within the university, we haven't wanted a science major to
> cost more than any other major.  The department to which we lose the
> most physics students is math.  A lot of students find math easier than
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> * * * Concerning buying a 200mA meter and modifying it for 2A
>
> Been there; done that.  The typical multimeter has a 200mV voltmeter at
> its heart.  This can become a 2A ammeter with the addition of a
> 0.100-ohm shunt resistor.  To maintain a 1% accuracy we need at least a
> 1% resistor, and we need to use it properly.  Mouser Electronics does
> list some 1% shunt resistors for $3.40 which would serve this purpose.
> To use them properly one ought to attach a pair of two-level (stackable)
> banana jack/plugs so the shunt resistor can plug into the jacks where
> the test leads normally go, and then the test leads can plug into that.
cut

> Michael D. Edmiston, Ph.D.
> Professor of Chemistry and Physics
> Bluffton University
> Bluffton, OH 45817
> (419)-358-3270
> edmiston@bluffton.edu