Fluke 179 FE 175,177,179 Users Manual - Page 12

Models 175, 177 & 179 Users Manual XW Measuring AC or DC Current Warning To avoid personal injury or damage to the Meter: • Never attempt to make an in-circuit current measure- ment when the open-circuit potential to earth is > 1000 V. • Check the Meter's fuses before testing. (See "Testing the Fuses".) • Use the proper terminals, switch position, and range for your measurement. • Never place the probes in parallel with a circuit or component when the leads are plugged into the current terminals. Turn power OFF, break circuit, insert Meter in series, turn power on. Understanding AC Zero Input Behavior of True RMS Meters Unlike averaging meters, which can accurately measure only pure sinewaves, True RMS meters accurately measure distorted waveforms. Calculating True RMS converters require a certain level of input voltage to make a measurement. This is why AC voltage and current ranges are specified from 5% of range to 100% of range. Non-zero digits that are displayed on a True RMS meter when the test leads are open or are shorted are normal. They do not affect the specified AC accuracy above 5% of range. Unspecified input levels on the lowest ranges are: • AC voltage: below 5% of 600 mV AC, or 30 mV AC • AC current: below 5% of 60 mA AC, or 3 mA AC HOLD MINMAX RANGE DC mA + + A CAT CAT AIK08F.EPS 8