Fluke 45 - Manual (Page 49)

45
Users Manual
4-2
CAL
ENABLE
V 10A
100
mA
600V CAT I
1000V CAT I
FUSE F1
500 mA
F 250V
POWER
AUTO
2ND
MN MX RATE
dB REL
REF# LOCAL
THRESH ADDR BAUD
HOLD
LO HI COMP
A
A V FREQ
DUAL DISPLAY MULTIMETER 45
V
!
REF
FUSED
COM
+ -
FREQ
V
2ND
AUTO
VAC
Hz
M
aam16f.eps
Figure 4-1. Dual Display Showing Volts AC and Frequency
Using Measurement Functions in Combination
The dual display allows you to display two properties of the input signal being measured.
Any combination of two properties from the list below is allowed, even those that may
not be useful:
Volts dc
Volts ac
Current dc
Current ac
Resistance
Frequency
Diode Test/Continuity
Note
Volts (dc + ac) rms or Current (dc + ac) rms measurements can only be
made in the primary display. While (dc + ac) measurements are being
made, another function cannot be selected for the secondary display.
Additional combinations of dual readings are added if you use the function modifiers—
i.e., REL, MN MX, HOLD, or dB.
Some applications of the dual display using common combinations of readings are
provided in Table 4-1.
Taking Voltage and Current Measurements Using the Dual Display
Most applications of the dual display listed in Table 4-1 can be performed using a single
set of test leads connected to the
Xand COM input terminals.
However, to measure the voltage and current of an input signal requires three leads. Be
sure that the voltage and current measurements share the same common as shown in
Figure 4-2. Then simply follow the precautions you would follow if you were making
normal current measurements without a current clamp.