[Boatanchors] DC Voltmeter Calibration

[Al Klase]

Dave,

That is correct.  Keep in mind that a really top-notch analog meter has 
a rated accuracy of something like 1% of full scale, when calibrated.  
That's +/- 3 volts in your case.  You might want to take a reading on a 
fresh battery as a sanity check.  Alkaline cells are about 1.59 volts, 
and as I recall, carbon-zinc (heavy duty) cells are something like 1.56 
volts.  In any event the average DMM is plenty accurate for calibrating 
a 20th-centrry analog instrument.

All this 21st Century stuff operates on the FM principle:  It's Freakin' 
Magic!

Al.

Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

On 1/7/2016 7:31 PM, David C. Hallam wrote:
> So, what you are saying is that the Metex ME11 DVM with a reading of 
> 331V is probably the closest to the true value of the B+?
>
> David
> KW4DH
>
> On 1/7/2016 3:36 PM, Al Klase wrote:
>> CORRECT ANSWER!!!
>>
>> Modern DVM's all contain band-gap references. These are semiconductor 
>> devices that use quantum-physical principles to generate a know 
>> voltage. They are much more accurate than anything else you're going 
>> to lay mortal hands upon. Sit down with a AA cell, and compare two or 
>> three DVM's. You'll be amazed.
>>
>> In my case:
>>
>> $300+ Fluke 87 1.588V
>> $70'ish Escort 1.589V
>> $11 Ebay cheapie 1.592V
>>
>> A VR tube or Zener diode won't even come close.
>>
>> Al
>>