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Checking the CAPACITANCE Control Calibration on the 1 Multiplier Range„
(1)
Test equipment: One each Capacitance Standard CS-1000, CS-500,
and CS-100 (Boonton Electronics Corporation), or equivalent 1000 pF,
500 pF, and 100 pF capacitance standards.
Two RG-58/U coaxial
cables, each approximately four inches long and terminated in BNC
connectors.
(2)
Procedure:
a,
Adjust the Model 75D front panel controls in accordance with
Table 4.
b.
Set the DIVIDE G/MULTIPLY R switch to 100.
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Connect one end of an RG-58/U cable to the REMOTE TEST HI
connector on the Model 75D front panel, and connect one end of
the other RG-58/U cable to the REMOTE TEST LO connector.
d.
Connect the free end of the REMOTE TEST LO cable to either
terminal on the CS-1000.
e.
Zero-balance the bridge as described in paragraph 3.5.
f.
Connect the free end of the REMOTE TEST HI cable to the
remaining terminal on the CS-1000.
g.
Adjust the CAPACITANCE and the CONDUCTANCE controls for
a null indication on the meter.
Read the CAPACITANCE dial.
h.
Correct for RG-58/U inductance by multiplying the length of the
cable pair (inches) by 0.58 pF and subtracting the product from
the CAPACITANCE dial reading derived in Step (g), above.
(For example, a four-inch cable pair is 4 X 0.58 pF = 2.32 pF,
which is subtracted from the CAPACITANCE dial reading.)
i.
Refer to paragraph 1 .4,a, and check the corrected pF reading
derived in Step h , above, for conformity with the capacitance
accuracy specification.
If the corrected pF reading is not
consistent with the accuracy specification, refer to the note at
the end of this procedure.
j.
Remove the CS-1000 from the coaxial cables.
k.
Set the CAPACITANCE control to zero and the CONDUCTANCE
control to G-scale zero.
l.
Connect the free end of the REMOTE TEST LO cable to either
terminal on the CS-500.
m.
Zero-balance the bridge as described in paragraph 3.5.
n.
Connect the free end of the REMOTE TEST HI cable to the
remaining terminal on the CS-500.
o.
Adjust the CAPACITANCE and CONDUCTANCE controls for a
null indication on the meter.
Read the CAPACITANCE dial.
p.
Correct for RG-58/U inductance by multiplying the length of
the cable pair (inches) by 0.16 pF and subtracting the product
from the CAPACITANCE dial reading derived in Step o , above.
75D
b-370
66
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