Maintenance
Performance Tests
3
3-9
3-15. AC Voltage Test
WWarning
Injury hazard. Connect the ground/common/low side of the AC
calibrator to common on the Fluke 78.
1. Set the Fluke 78 rotary switch to
K
and connect the AC Voltage Calibrator to the
z and COM input terminals.
2. Set the AC Voltage Calibrator for the output given in Table 3-3, and verify that the
Fluke 78 display reading is within the limits shown in the table.
3. Reset the source to 0 V.
Note
When the input is open in the V AC function, it is normal for the meter to
read some counts on the display. This is due to the ac pickup in the ac
amplifier when the ac amplifier is unterminated.
Table 3-3. AC Voltage Test
Step
Input
Display Reading
Range Voltage Frequency
1 4 V short ---- 0 to .002 V AC
2 4 V 3.500 V 100 Hz 3.410 to 3.590 V AC
3 4 V 3.500 V 1 kHz 3.410 to 3.590 V AC
4 40 V 35.00 V 1 kHz 34.10 to 35.90 V AC
5 300.0 V 350 V 1 kHz 341.0 to 359.0 V AC
6 300 V 500 V 1 kHz 485 to 515 V AC
3-16. Frequency Test
1. Set the Fluke 78 rotary switch to HzB and press the pushbutton for 2 seconds to put
the meter in the ac-coupled frequency function.
2. Connect the Function Generator output to the z and COM input terminals of
the meter.
Note
The frequency accuracy of the Function Generator must be appropriate
for the specified accuracy of the Fluke 78.
3. Referring to Table 3-4, set the Function Generator for the output indicated in the
steps. Verify that the Fluke 78 display reading is within the limits shown in the table.
Table 3-4. Frequency Test
Step
Sine Wave Input
Display Reading
Range Voltage Frequency
1 4 V 300 mV rms (848 mV p-p) 20 kHz 19.98 kHz to 20.02 kHz
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