21
Making Measurements
never try to measure an AC volt-
age above 750 volts RMS.
1. Set the function selector to
dBm /
~ V
.
2. Repeatedly press
SELECT
to
select the measurement unit you
want to use (dBm or volts).
Notes:
• 0 dBm is equal to the con-
sumption power on a 600-ohm
resistor with 0.775V voltage
drop.
• In dBm mode, relative mea-
surement and monitor modes
are disabled.
3. If the meter is set to automatic
range control, the meter auto-
matically move to the range that
gives the best reading.
4. To set manual range control,
press
RANGE
then change the
range (if necessary) by repeat-
edly pressing
RANGE
.
5. Touch the probes to the circuit
you want to test.
Note: In the 400 V and 400mV rang-
es, the decimal point appears in the
same position (one place to the left).
To distinguish between the two rang-
es,
mV
appears in the 400mV range
and
V
appears in the 400 V range.
Measuring AC Voltage
Riding on a DC Source Bias
WARNING: To avoid injury or dam-
age to your meter, never try to mea-
sure an AC voltage that is riding on a
DC source bias where the peak AC
voltage exceeds 1000 V with respect
to earth ground.
To measure AC voltage superim-
posed on a DC voltage source bias
while ignoring the DC voltage, follow
the steps for measuring AC voltage
under “Measuring AC Voltage” on
Page 20.
Measuring Three-Phase AC
Voltage
Your multimeter is designed primarily
to measure household AC voltages. If
you want to measure 3-phase, line-to-
line voltage, please note the follow-
ing:
• Because of the dangers inherent
in measuring three-phase circuit,
we strongly recommend you do
not use this meter for such appli-
cations.
• The actual voltage can be
greater than the circuit’s rated
line-to-ground voltage.
Most 3-phase power circuits are rated
by their line-to-line voltage. This volt-
age is higher than the line (or phase)
to ground voltage. To determine if a
line-to-line 3-phase voltage exceeds
the rating of this meter, multiply the
