Series 3700 System Switch/Multimeter User's Manual
Section 5: Basic Digital Multimeter (DMM) Operation
3700S-900-01 Rev. C / July 2008
5-25
AC voltage offset
The Series 3700, at 5½ digits resolution, will typically display 100 counts of
offset on AC volts with the input shorted. This offset is caused by the offset of
the TRMS converter. This offset will not affect reading accuracy and should not
be zeroed out using the REL feature. The following equation expresses how this
offset (VOFFSET) is added to the signal input (V
IN
):
Example:
Range= 1VAC, Offset = 100 counts (1.0mV), Input = 100mV RMS
Therefore, the displayed reading is 0.100005V.
The offset is seen as the last digit, which is not displayed. Therefore, the offset
is negligible. If REL were used to zero the display, the 100 counts of offset
would be subtracted from V
IN
, resulting in an error of 100 counts in the displayed
reading.
Current measurements (DCI and ACI)
The Series 3700 can make DCI measurements from 1pA to 3A and ACI
measurements from 1mA to 3A RMS.
WARNING
To prevent electric shock, never make or break
connections while power is present in the test circuit.
NOTE
Also see crest factor information contained in
AC voltage
measurements and crest factor
(on page 5-13).
AMPS analog backplane fuse replacement
WARNING
Make sure the instrument is disconnected from the power
line and other equipment before replacing the AMPS fuse.
