Fluke 80 Series III User Manual page 21

The following are some tips for measuring voltage:
When you measure voltage, the meter acts
approximately like a 10 M
impedance in parallel with the circuit. This loading
effect can cause measurement errors in high-
impedance circuits. In most cases, the error is
negligible (0.1% or less) if the circuit impedance is
10 k (10,000 ) or less.
For better accuracy when measuring the dc offset of
an ac voltage, measure the ac voltage first. Note the
ac voltage range, then manually select a dc voltage
range equal to or higher than the ac range. This
procedure improves the accuracy of the dc
measurement by ensuring that the input protection
circuits are not activated.
(10,000,000 )
AC Voltage
87 III TRUE RMS MULTIMETER
MIN MAX RANGE HOLD H
REL Hz
41/2 DIGITS PEAK MIN MAX
1 Second
mV
mA
V A
A
V
V
OFF
A mA A COM V
!
400mA MAX
CAT II
FUSED
10A MAX 1000V MAX
FUSED
!
DC Voltage
87 III TRUE RMS MULTIMETER
MIN MAX RANGE HOLD H
REL Hz
PEAK MIN MAX
41/2 DIGITS
1 Second
mV
mA
V V A
A
V
OFF
A mA A COM V
!
400mA MAX CAT II
FUSED
10A MAX 1000V MAX
FUSED
!
Figure 2. Measuring AC and DC Voltage
Making Measurements
Switch Box
+
iy2f.eps
13