Keysight Technologies 3458A Guide D'utilisation page 89

Resistance
The multimeter measures resistance by supplying a known current through the
unknown resistance being measured. The current passing through the resistance
generates a voltage across it. The multimeter measures this voltage and
calculates the unknown resistance (resistance = voltage/current).
each 2-and 4-wire ohms range and its full-scale reading (the full scale reading
also shows the maximum number of digits for each range).
the maximum resolution and current sourced for each range. (Resolution is a
function of the specified integration time: refer to
later in this section for more information.)
Table 3-6
2-wire ohms
Two-wire ohms is most commonly used when the resistance of the test leads is
much less than the value being measured. If the lead resistance is large compared
to the resistance to be measured, readings will be inaccurate. For example,
suppose you are measuring a 1 W resistor located 10 feet away. If you use
24-gauge copper wire to make the connections, the 20 feet of leads contribute
about 0.5 ohms to the measurement. This makes the total measurement
1.5 ohms--an error of 50%. Some other factors that may cause high lead
resistance are loose or dirty connections, kinked or damaged wires, or a very hot
Keysight 3458A User's Guide
Resistance ranges
OHM(F) range Full scale read ing
10 W
100 W
1 kW
10 kW
100 kW
1 MW
10 MW
100 MW
1 GW
Maximum resolution
12.00000 W
120.00000 W
1.2000000 kW
12.000000 kW
120.00000 kW
1.2000000 MW
12.000000 MW
120.00000 MW
1.2000000 GW
Configuring for Measurements
Table 3-6
Setting the integration time
10 µW
10 µW
100 µW
1 mW
10 mW
100 mW
1 W
10 W
100 W
3
Table 3-6 shows
also shows
Current sourced
10 mA
1 mA
1 mA
100 µA
50 µA
5 µA
500 nA
500 nA
500 nA
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