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Spring 2008 Instructor: David Politzer e-mail: politzer.theory.caltech.edu
Q: If I have a multimeter that's easier to use and more accurate, may I use it on the labs?
A: You might be surprised, but the answer is a definite NOPE.
There are a few good reasons. First of all, the physics of our (albeit chintzy) analog multimeters is part of the syllabus. We learn how they work and how they perform. We see their limitations and learn how to correct for them. And we learn to extend their capabilities.
Second, you have to know what you're doing to use it. In particular, unlike many really good meters, ours are not "self-ranging." There are even yet classier meters that figure out for themselves what you want to know based on what you connect them to; so you don't even have to choose resistance, voltage, or current -- AC or DC.
Third, we learn something about measurement uncertainty from trying to read an analog scale. In contrast, most students when using a meter with a digital output would simply write down however many significant figures the meter provides, without thinking which of those digits were reliable or relevant.
And finally, our meters provide more than enough "accuracy" for our experiments. In general, we will be comparing observations with our expectations. The latter are based on simple, sound physics but certainly ignore many real effects. Knowing more physics, we could, in principle, improve our "theory." But within the range of activities described in ZAP!, we will not run into situations where the most serious limitation is the accuracy of our meters.
(Don't throw that good meter away! After Ph 1, you'll have even more use for it.)
Return to the Ph 1 Prac main page page.
The Caltech Main Page contains links to other Caltech sites.