Calculating Ac Characteristics Accuracy; Calculating Db Characteristics Accuracy - Keithley 3700 Series User Manual

Series 3700 System Switch/Multimeter User's Manual
For example, to calculate the accuracy of the above example at 0.006plc:
Accuracy =
DC current and resistance calculations are performed in exactly the same
manner using the pertinent specifications, ranges, and input signal values.

Calculating AC characteristics accuracy

AC characteristics accuracy is calculated similarly, except that AC specifications
are given as follows:
Accuracy = (% of reading + % of range)
As an example of how to calculate the actual reading limits, assume that you are
measuring 120V, 60Hz on the 300V range. You can compute the reading limit
range from ACV one-year accuracy specifications as follows:
Accuracy =
In this case, the actual reading range is: 120V± 0.162V or from 119.838V to
120.162V.
AC current calculations are performed in exactly the same manner using the
pertinent specifications, ranges, and input signal values.

Calculating dB characteristics accuracy

The relationship between voltage and dB is as follows:
3700S-900-01 Rev. C / July 2008
+/- (( 25ppm of reading) + ( 2ppm of range ) + ( 2.5 x 7ppm of range ))
= +/- (( 25ppm x 5V ) + ( 2ppm x 10V ) + ( 2.5 x 7ppm x 10V ))
= +/- ( 125uV + 20uV + 175uV )
= +/- 320uV
±(0.06% of reading + 0.03% of range)
±[(0.0006 × 120V) + (0.0003 × 300V)]
±(0.072V + 0.09V)
±0.162V
Section 5: Basic Digital Multimeter (DMM) Operation
5-75