Fluke 45 - Manual (Page 108)

45
Users Manual
Decibel Reference Resistance
8000
Ω
1200
Ω
1000
Ω
900
Ω
800
Ω
600
Ω
*
500
Ω
300
Ω
250
Ω
150
Ω
135
Ω
125
Ω
124
Ω
110
Ω
93
Ω
75
Ω
50
Ω
16
Ω
†
8
Ω
†
4
Ω
†
2
Ω
†
* Default resistance
† Reading displayed in watts (POWER)
Input Impedance
1 M
e in parallel with <100 pF
Maximum Crest Factor
3.0
Common Mode Rejection Ratio
>60 dB at 50 Hz or 60 Hz (1 k
e unbalanced medium rate)
Maximum Input
750 V rms, 1000 V peak
2 X 107 Volt-Hertz product on any range, normal mode input
1 x 106 Volt-Hertz product on any range, common mode input
(AC + DC) Voltage Accuracy
Total Measurement Error will not exceed the sum of the separate ac and dc accuracy
specifications, plus 1 display count. Refer to the table under "Maximum Allowable AC
Voltage while Measuring DC Voltage or (AC + DC) Voltages" located on page A3.
Note
When measuring ac + dc, (or any dual display combination of ac and dc) in
the fast reading rate, the Fluke 45 may show significant reading errors.
This results from a lack of filtering on the dc portion of the measurement
for the fast reading rate. To avoid this problem, use only the "slow" and
"medium" reading rates for ac + dc or ac and dc combinations.
Maximum Frequency of AC Voltage Input While Measuring AC Current
When the meter makes ac current and ac voltage measurements using the dual display,
the maximum frequency of the voltage input is limited to the maximum frequency of the
current function. For example, if you are making an ac current measurement on the 10 A
range, the maximum frequency of the voltage input must be less than 2 kHz.