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Re: [Phys-l] glassware needed

On Jan 1, 2009, at 8:08 PM, Brian Whatcott wrote:

At 06:38 PM 1/1/2009, Ludwik, you wrote:

I would use a d.c. power supply (measuring I and U and
calculating the input energy as U*I*t).

Would the I and V readings be taken with an analog meter (+-5%)
or an inexpensive DVM (+-1 count and <1% often)
and an inexpensive DC power supply ( ripple +- 3%), I wonder, Ludwik?

That depends on the acceptable accuracy (systematic error) and precision (random error).

Ludwik Kowalski, a retired physics teacher
5 Horizon Road, Apt. 2702, Fort Lee, NJ, 07024, USA
Also an amateur journalist at