Fluke fluke

[Martin Czech]

This Metex M4640A multimeter was cheap.  So cheap that I was
suspicious....


Ok, take it to the lab, pull out the 2000 Euro  Fluke, whoaa, what is
this ? 10% Error. Oh no, wasted money.  No , can't be. Pull aut the
13000 Euro HP3458A, this is the best I can get in our lab. Ahhhhh,
smiiiiiile. The Fluke is corrupted, not my el cheapo Metex.


So, what can I expect:

(I write this precious data down, best into a mail, so I can't
loose it.)


DC-Voltage

HP3458A   M4640A   Error %

0.05097   0.05098  0.019    no scale error due to no divider
0.08495   0.08495  0.000
0.11906   0.11906  0.000
0.14803   0.14805  0.014
0.19903   0.19904  0.005

0.19903   0.1987   -0.165  (Range)
0.20003   0.1997   -0.165
0.40005   0.3996   -0.112   
1.00000   0.9992   -0.080
1.50012   1.4989   -0.081
1.9976    1.9961   -0.075  divider network makes about 0.08% error

1.9976    1.995    -0.13   (Range)
4.2977    4.293    -0.11
8.7979    8.791    -0.078  
10.000    9.992    -0.080
16.300    16.290   -0.062
19.986    19.973   -0.068  divider network makes about 0.07% error

So the M4640A ADC seems to be very linear, to my surprise, but the
resistive divider network used for 2V and 20V full scale introduces some
scale error.


Ohms:

HP3458A   M4640A    Error %
51.157    51.21     1.2
99.79     99.95     1.6
199.61    199.6     -0.005
389.3     389.3     
817.6     817.4
1593.7    1593.3
3307.7    3310      +0.070
9999.7    9999
17944     17942
100088    100070    -0.018
179530    179500
1.1121M   1.1116M
4.7038M   4.704M
10.057M   10.058M


Huu, that's really good for el cheapo. I don't belive the first
two values, cause I had serious contact problems.

El cheapo multimeters are quite good today, better then I expected.
0.1% tolerance is the spec sheet value.

m.c.