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Re: Power Supply requirements



To state the obvious, the proper supply depends on what you want to
do. Magnets need up to a few amps, while electrical experiments can
use much less.

Here we run most of a typical range of freshman/sophomore experiments
on two supplies:

Adjustable 0-10V, current limited to 120 mA for circuits, e/m magnetic
deflection, etc. The big advantage of the low power is that students
can't destroy much, not even the supply. This unit is home-made.

A 13.6 V fixed 2.5 A supply intended for auto radio servicing. This
supplies constant fields for a couple of experiments. We have had
students kill these with near-shorts, so we are adding output
fuses in the hope of saving transformers. At least theyr'e cheap,
about $25.

Our e/m experiment was taken from the Berkeley course and uses a
CRT. We run the tube on an ancient Heath vacuum tube supply and built
a +/- 30V negligible current supply for deflection. We also run a
power amp to drive a vibrating wire off a crude supply that give about
2A at 15V unregulated. It would have been easy, and better, to build a
dedicated supply but I haven't gotten around to it.

I guess I would start with the basics and then build up as time and
money allow.

Hope this is of some assistance.

Stan



I am putting together and introductory physics laboratory program. Can
anyone suggest specific requirements for power supplies for use in lab?
I.E. voltage and current ranges suitable for experiments.
I have catalogs that have good PS's that range 0-18V at 5A, and ones that
range 0-30V at 3A. Which would be more suitable?