Re: [Phys-L] Error propagation measuring Resistance with Volt-Ampmethods

["John Clement" <clement@hal-pc.org>]

If the students are just following a recipe, then it is a useless exercise.
They need to be doing measurements where they understand what they are doing
rather than just follow steps.  Now one thing that might be useful would be
to ask the students to estimate which has a larger effect on the
measurement, the insertion error, or the instrument error, and explain how
they figured this out.

John M. Clement
Houston, TX


> I'm putting together a laboratory experience about resistance 
> measurement  with voltmeter and ammeter, with its two 
> variants: the 'short' method  and the 'long' method. I know 
> the formulas to determine errors made by instrument insertion 
> into the circuit (due to internal resistance of the 
> instruments) in each case,  on the other hand, the 
> manufacturer states that the ammeter have an error equal +-Ae 
> and the voltmeter have an error equal +-Ve.
> I want to make the insertion of the instrument's errors,  Ae 
> and Ve, in the short method and long method formulas, and 
> calculate error  propagation, in order to compute the total 
> error using the real instruments with both methods,  but I 
> can not find a detailed deduction with a step by step 
> procedure, in order to let students follow it alone. I would 
> appreciate  if someone can  help me, or tell me about relate 
> literature.
>
> Thanks for your attention. My best regards.