[Amps] The Philosophy of Science

[MorgusMagnificen at aol.com]

Your digital meter question brings up a good point. Unfortunately, the whole 
situation here is a little more complex than you might like.

First, the overall accuracy of your meter is determined by more than the 
readout device. In particular, a DVM contains an A/D converter and a voltage 
reference, both of which contribute equally to its accuracy. Second, you 
cannot accurately, or consistently, make readings with 4 digits of accuracy 
on even the best analog meter. If you look at specs on analog meters, you 
will hardly ever (never?) see meters with 1% accuracy, but digital meters can 
do that regularly. Also, the linearity of electrodynamic panel meters is not 
perfect.  When I started in electronics, analog meters were considered 5% 
instruments at best.

In summary, you cannot make a good decision based upon just the facts given. 
I will say that in my experience reputable DVM's are more accurate than 260's 
were, and I am not just talking about the 4th significant figure. The issues 
of accuracy and resolution are really independent of each other.

As far as your 12-digit calculations based upon your 4 digit DVM readings - 
the 8 least significant digits are garbage (or at least 7 of them are - let's 
not get into issues about so-called 1/2 digits.)

Keep your slide rule on hand for when your calculator battery dies. If you 
use solar powered ones (which I do finally) then you should also keep it on 
hand for when the sun wobbles out of orbit, or we do.

Eric K8LV