Digital Multimeters for Dummies

[Paul Perry]

At 06:54 AM 7/11/98 -0800, you wrote:
>Subject:  Digital Multimeter Basics / Questions 

>The Count:  The higher the count, the better because this is the number
>of samples used to calculate the measurement.  True or false?
.....true. Usually this just means the 'biggest number' it reads out.

>True RMS:  True root mean square.  If it doesn't say true RMS, it is
>making measurements how?  Is this cheap alternative measurement
>system really that awful?
.....it doesn't worry me. A cheap one will read true RMS for a sinewave,
anyhow.
>
>Percent Accuracy:  What is completely unacceptable for high quality
>amateur work?
....depends what you are doing.
1% suits me fine. I could live with 2%.
>
>Certificate of Calibration:  Do I need this 
.fuck no.

>Autoranging vs. Manual Setting:  
I think autoranging is a hassle.
The impedance of the meter changes with scales usually, so this can
be a problem in comparison situations. But, not probably a problem 
for what you are doing.


>Frequency:  Is this really a useful function on a handheld multimeter
Sometimes. Your tuner is more accurate, but only for the musical notes.

>3 1/2 Digit:  Does the half digit at the end mean that measurements
>are rounded to one decimal place?
Means counts to 2000.

  I saw a Fluke with 3 3/4 digits.
>What does the 3/4 digit mean?
Prob means counts to 4000 ( i cd be wrong)
>
>Two general questions...
>Multimeters, even those with the same features (accuracy, functions, 
>etc...), seem to range wildly in price.  Are you paying for a real
>difference in quality or are you paying extra for a brand name
>that doesn't really mean anything?
Both. And, servicing.
>
>Is it possible for a low cost multimeter to really be good at a large
>number of functions, from DC to AC, to transistor testing, to
>resistance, capacitance, and frequency? 
Well I'm perfectly happy with a 'no name' $80 2000 count one.
And, I really need the transistor checker, because you can use it to
find which way the transistor goes (just plug in in diferent ways 
until you get a big hfe reading)

paul perry melbourne australia 

BTW, isn't this covered on Paul Schreiber's site? after all, he 
DESIGNED the best cheap multimeter in USA!