Fluke 8842a Making Measurements, Input Overload Protection Limits, Measuring Current

Operating Instructions 2

MAKING MEASUREMENTS

2-24. MAKING MEASUREMENTS

2-25. Input Overload Protection Limits

WARNING

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

Table 2-2. Input Overload Limits

CONNECTORS MAXIMUM INPUT

VDC

MA DC

2 WIRE/4 WIRE kΩ

VAC

INPUT HI and LO:

2A INPUTand INPUT LO:

INPUT HI and LO:

SENSE HI and LO:

INPUT HI and LO:

1000 dc 2000mA

300V rms

300V rms

700V rms, 1000V peak, or 2 x 107 V-Hz (whichever is less)

MA AC

All Funtions

2A INPUT and INPUT LO:	2000 mA rms
Any terminal to earth:	1000V dc or peak ac

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.

WARNING

TO AVOID ELECTRIC SHOCK, REMOVE THE TEST LEADS

BEFOREREPLACING THE FRONT PANEL FUSE.

2-13