Ac Voltage Test; Frequency Test - Fluke 78 Service Manual

3-15. AC Voltage Test

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.
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.
Step
1
2
3
4
5
6

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.
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.
Step
Range
1 4 V
WWarning
Note
Table 3-3. AC Voltage Test
Input
Range Voltage
4 V short
4 V 3.500 V
4 V 3.500 V
40 V 35.00 V
300.0 V 350 V
300 V 500 V
Table 3-4. Frequency Test
Sine Wave Input
Voltage
300 mV rms (848 mV p-p)
Frequency
----
100 Hz
1 kHz
1 kHz
1 kHz
1 kHz
Note
Frequency
20 kHz
Maintenance
Performance Tests
Display Reading
0 to .002 V AC
3.410 to 3.590 V AC
3.410 to 3.590 V AC
34.10 to 35.90 V AC
341.0 to 359.0 V AC
485 to 515 V AC
Display Reading
19.98 kHz to 20.02 kHz
3
3-9