Measuring Ac Voltage - Fluke 87 Series IV User Manual

Model 87 & 89 Series IV
Users Manual
When measuring voltage, the meter acts like a 10 M
(10,000,000 ) 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
or less.

Measuring AC Voltage

The meter presents ac voltage values as rms (root mean
square) readings. The rms value is the equivalent dc
voltage that would produce the same amount of heat in a
resistance as the measured voltage. Your meter features
true rms readings, which are accurate for sinewaves and
other wave forms (with no dc offset) such as square
waves, triangle waves, and staircase waves. For ac with
$
.
dc offset, use
Set up the meter to measure ac volts as shown in Figure
3-1.
All pushbutton features are available in this function. The
blue button ( %) accesses decibel dBm or dBV)
measurements, discussed next in this chapter.
3-2
(10,000 )
V V
dB dB
89 LOGGING MULTIMETER
AutoHOLD FAST MN MX LOGGING YES
HOLD HOLD MIN MAX MIN MAX REL REL
NO
CANCEL SAVE
Hz Hz % % ms ms RANGE RANGE
SETUP
nS nS
F F
mV mV
C C
ac+dc ac+dc
A A
V V mA mA
ac+dc ac+dc
mV mV A A
dB dB
A A
V V
dB dB mA mA
ac+dc ac+dc
A A
OFF OFF
ac+dc ac+dc
VIEW
CLEAR MEM
TEMPERATURE TEMPERATURE
mA mA
A A COM COM V V
A A
10A MAX
CAT
400mA
FUSED
FUSED 1000V
Figure 3-1. AC Voltage Measurement
Switch
Box
tc001f.eps