732B/734A
Instruction Manual
5-6
The lowest bcd switch setting is "0000" and the highest is "3999" (in the most significant
to least significant bit order). This range of settings represents total adjustment of 400
ppm (4 mV) minimum, with a resolution of approximately 1 µV. Typically, the bcd
setting for an exact 10.0V will range from 1400 to 2200.
Calibration with Adjustment 5-8.
Complete the following procedure to standardize the output of the 732B to a Certified
732B. Verify that for the UUT, the 24-hour warmup period on ac line power has been
met. Always set the null detector to ZERO when changing leads.
Proceed as follows to calibrate the 732B:
1. Obtain a certified 732B or 732A to use as the reference standard.
Caution
To avoid cracking or jamming the plastic binding post insulators,
tighten them only with finger pressure. Do not use tools.
2. Connect the UUT, certified 732B, and null detector as shown in Figure 5-1.
3. Set the OPR switch on the null detector to the ZERO position. Adjust the null
detector for zero on the 3 µV range.
4. Set the null detector to the 30 µV range and the OPR switch to OPR. If the null
detector needle is pegged, set the range to 100 µV.
5. Adjust the 1.0 ppm bcd switch until the null detector reads less than 10 µV positive
or negative.
Note
If the switch reaches "0" and the null detector is more positive than 10 uV,
adjust the 10 ppm bcd switch down one setting. If the 10 ppm bcd switch
is already at "0", adjust the 100 ppm switch down one setting and set the
10 ppm bcd switch to "9". Continue adjusting the 1.0 ppm bcd switch
until the null detector is within 10
µ
V.
Note
If the switch reaches "9" and the null detector is more negative than -10
µ
V,
adjust the 10 ppm bcd switch up one setting. If the 10 ppm bcd switch is
already at "9", adjust the 100 ppm switch up one setting and set the 10
ppm bcd switch to "0". Continue adjusting the 1.0 ppm bcd switch until
the null detector is within 10
µ
V.
6. Set the null detector to the 10 µV range and adjust the 0.1 ppm bcd switch until the
null detector reads less than 3 µV, positive or negative.
7. Set the null detector to the 3 µV range. Set the OPR switch on the Null Detector to
the ZERO position. Readjust the null detector for zero, if necessary.
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