Making Measurements; Input Overload Protection Limits; Measuring Voltage And Resistance; Measuring Current - Fluke 8842A Instruction Manual

2-24. MAKING MEASUREMENTS

2-25. Input Overload Protection Limits

TO AVOID SHOCK HAZARD AND/OR INSTRUMENT DAMAGE,
DO NOTAPPLY INPUT POTENTIALS THAT EXCEED THE INPUT
OVERLOAD LIMITS SHOWN IN TABLE 2-2.
The 8842A is protected against input overloads up to the limits shown in Table 2-2.
Exceeding these limits may damage the instrument and/or pose a shock hazard.
FUNTION
VDC
MA DC
2 WIRE/4 WIRE k
VAC
MA AC
All Funtions

2-26. Measuring Voltage and Resistance

To measure voltage or resistance, select the desired function and connect the test leads as
shown in Figure 2-9. Resistance can be measured in either the 2-wire or 4-wire
configuration.

2-27. Measuring Current

To measure current, select the desired function and connect the test leads as follows:
1. Turn off power in the circuit to be measured (Figure 2-10).
2. Break the circuit (preferably on the ground side to minimize the common mode
voltage), and place the 8842A in series at that point.
3. Turn on power in the circuit, and read the display.
4. Turn off power in the circuit, and disconnect the 8842A.

2-28. Current Fuse Protection

The 2A input terminal is protected from overloads by a 2A, 250V fuse which is
accessible from the front panel, and by an internal 3A, 600V fuse. If either fuse blows,
the 8842A will respond as though the input were zero.
TO AVOID ELECTRIC SHOCK, REMOVE THE TEST LEADS
BEFOREREPLACING THE FRONT PANEL FUSE.
WARNING
Table 2-2. Input Overload Limits
CONNECTORS
INPUT HI and LO:
2A INPUTand INPUT LO:
INPUT HI and LO:
SENSE HI and LO:
INPUT HI and LO:
2A INPUT and INPUT LO:
Any terminal to earth:
WARNING
Operating Instructions
MAKING MEASUREMENTS
MAXIMUM INPUT
1000 dc
2000mA
300V rms
300V rms
700V rms, 1000V peak, or 2 x 10
V-Hz (whichever is less)
2000 mA rms
1000V dc or peak ac
2
7
2-13