XPost: sci.electronics.equipment   
   From: presence@MUNGEpanix.com   
      
   In sci.electronics.equipment Commander Kinsey  wrote:   
   > On Wed, 24 Jun 2020 21:06:04 +0100, Rich  wrote:   
   >   
   >> In sci.electronics.equipment Commander Kinsey    
   wrote:   
   >>> On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom  wrote:   
   >>>   
   >>>> On 6/18/2020 6:33 PM, Commander Kinsey wrote:   
   >>>>> I just bought an amp clamp meter, and it states the error is "+/-   
   >>>>> 1.9% + 3 digits".  What does the "3 digits" part mean?   
   >>>>>   
   >>>>   
   >>>> If your meter should read, say 1.875 A, the correct reading could   
   >>>> be anywhere from 1.872 to 1.878. This is a possible error in the   
   >>>> display presented to you in the analog-digital display conversion   
   >>>> process. The +/-1.9% possible error is about the measurement   
   >>>> taken including - but not only - any error made by the sensor.   
   >>>   
   >>> Thanks, I wonder why all my other meters only list a % error.  Is it   
   >>> included within it somehow, or are they just lying, or do some meters   
   >>> not have this error?   
   >>   
   >> One generally finds the percentage plus digits error measures on more   
   >> expensive equipment.  Less expensive equipment more often than not only   
   >> lists a percentage and nothing more.   
   >   
   > So should I assume the cheaper ones are lying?  Or have they just made a   
   rough estimate adding the two errors?   
      
   might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might   
   have been from a raffle or something like that.   
      
   The DC voltage specs range from 0.8% +1 digit (not bad really)  over to the   
   AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it   
   with outlet voltage, but would stay away from 208volts. The meter has 3.5   
   digits or max display of 1999. I'm figuring a real 100volt AC reading could   
   be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance   
   on the display or count. so 100volts from your Japanese outlet reference   
   might read 98 to 102 volts. So while in the ballpark, it's better than you   
   can read off a Simpson 260 meter in the AC voltage range. I could be wrong   
   on this too.   
      
   It's a pretty decent meter for poking at DC circuits for the tens of   
   dollars is must have cost when new.   
      
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