[Elecraft] KPA100 resistance checks

[Don Wilhelm]

Mike,

Nornally voltage measurements that are less than 5% away from their 
nominal values are just fine.
In your case however, the target value was stated as having 2 
significant digits - so just round your reading to 2 significant digits 
as well,
Your 3.076 volt measurement rounds nicely right to the target value of 
3.1 volts.

/rant on
Alas, when are those with many digits of display on their meter going to 
discover that just because the meter shows all those digits, many times 
(most times) those lower order digits are not always significant.
If you are measuring something nominally at 10 volts and your reading is 
anywhere between 9.5 and 10.5 it is close enough to 10 volts (except in 
special cases.  There is no sense fretting about it because the measured 
voltage is 9.899 volts instead of 10 volts.  Do we get the idea - just 
round the value you measure up to the number of significant digits 
expressed in the nominal value.

When do those extra digits become significant?  Well, if you are 
measuring something that is supposed to have 1% precision, then 3 
significant digits are called for - and add to that the fact that for 
most digital meters, the last digit displayed has a variability of +/-1 
count, so in this case, 4 significant digits could be called for., but 
when we measure things in a circuit which uses 10% tolerance capacitors 
and 5% tolerance resistors,  2 significant digits are enough to 
consider, occasionally 3.

/rant off

73,
Don W3FPR

Mike Weir wrote:
> Good afternoon all,
> With my KPA100 I am doing the resistance check on page 21 of the manual and for U1 pin 4 to ground I am getting 3.076 and not the 3.1 is this a problem?
> Mike
> VE3WDM
>
>