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If the above dial accuracy checks fail to meet the required specifications,
refer to Paragraph 5-15 for calibration procedures .
5-7 .
FLATNESS CHECK .
a .
Connect the equipment as shown in Figure 5-2 .
NOTE
The BUCKING SUPPLY should be constructed from
the components listed in Table 5-1 .
The 500 ohm
control should be used as a coarse adjust and the 50
ohm
control should be used as a fine adjust .
Set the Model 204C RANGE switch to X1K and the frequency dial to 1.
Set
the AMPLITUDE control to maximum output.
c .
Adjust the BUCKING SUPPLY 50 ohm
fine control for minimum
resistance,
and record the THERMAL CONVERTER output as
indicated on the
DC
NULL VOLTMETER .
Adjust the BUCKING SUPPLY coarse and fine controls for a OV indication
on the DC NULL VOLTMETER .
Do not readjust the
BUCKING SUPPLY
controls for the remainder of this check.
Check the Model 204C flatness at the frequencies listed in Table 5-3 for
the tolerances indicated .
The THERMAL CONVERTER is considered a square
law device .
Therefore , theoretically , the percent of
change
at
the output of the THERMAL CONVERTER
should be 2 times the percent of change at the input.
Actually the value is not quite 2. The number is typi
cally 1.7 .
Check the Calibration Report supplied with
your THERMAL CONVERTER for the exact multiplier .
ELECTRONIC COUNTER
hp5532A
204C - B - 1587
Figure 5-1 .
Dial Accuracy Check
5-2
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