General > General Technical Chat

Poll : The multimeter Brand that you favor Most in the last 10 Years.

<< < (3/3)

saturation:
Here's an interesting tidbit about my 1989 circa Fluke 85, series one [now now longer made.]  Another reason to go Fluke whenever possible, its over 20 years old.

Like the 87 V, Its got a 200kHz frequency counter, but I've never tested it to its limits, as I use it mostly for audio.  I found it will read square waves up to 800kHz, the major issue is that its down -3dB or so > 200kHz, but switching mV AC ups its sensitivity.  Above 800kHz, it just stops and won't go further, no wrong readings to worry about.  I compared its accuracy against a stand alone frequency counter, a recently calibrated DDS's frequency counter/generator and manually rechecked all readings using a scope.  Its spot on accurate to 4 digits as a frequency counter.

Also its non- true RMS AC reads accurately to over 100kHz, square waves.  Far higher for sine waves.  What I find amazing is the my calculated accuracy, using my crude instruments, is above the published specs, so its accurate beyond my capacity to resolve errors.

I then compared it against my 3 other DMMs and its amazing how they can't live up to the 85.  

I built a Sabtronics DMM with known good DCV, and its holding its own against the Fluke only in DC and AC only up to 200Hz.  The Sanwa and Radio Shack pocket DMM don't even come close.


switcher:
I too, own and use a Fluke 85.
AFAIK, the only difference between it and the Fluke 87, is that the 87 is TRMS.
If you look at the specs for the 83, 85, and 87 series1. The 83 has lower accuracy, but the 85 and 87 specs are identical, except the 87 is TRMS.
I've often wondered if the 85 is a downgraded 87.

saturation:
I think it is.  Its one reason they stopped making it, it cannibalized 87 sales.  I think I posted some pages of its specs from the calibration manual on this forum somewhere, the non-true RMS algorithm used is more accurate in some conditions than the 87, series one.  I don't know how it will do with harmonics, but I tested it too with square wave readings to emulate that, and at least to 100kHz it reads true.  Thus, it again does well without true RMS.


--- Quote from: switcher on May 16, 2010, 01:45:12 pm ---I too, own and use a Fluke 85.
AFAIK, the only difference between it and the Fluke 87, is that the 87 is TRMS.
If you look at the specs for the 83, 85, and 87 series1. The 83 has lower accuracy, but the 85 and 87 specs are identical, except the 87 is TRMS.
I've often wondered if the 85 is a downgraded 87.

--- End quote ---

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version