Boonton Electronics 71A, 71AR - Page 26

references traceable to the National Bureau of Standards.
It provides a particularly convenient means for checking
the calibration of the Model 71A for both high Q and low 0
(0=3) measurements.
3.10.2 Calibration Check of the Model 71A with the
Model 71-1A Standard capacitor
(a) Remove all cables and adapters from the "TEST" and
"STD" terminals.
(b) set the instrument to the 1 pF range and adjust
the "CaMP ADJ" control as explained in paragraph
3.3.2.2.
(c) After zeroing the instrument on the 1 pF range,
switch to the 100 pF range.
(d) Plug the Model 7l-1A into the test terminals of
the Model 71A and observe the reading.
(e) Depress the switch on the case of the Model 7l-lA
and again observe the reading.
If a reading of 100 pF is obtained for both readings the in-
strument is in calibration. Otherwise, perform the follow-
ing calibration adjustments:
(a) With the Model 7l-lA connected at the "TEST"
terminals and without depressing the switch, set
the rear-panel "CAL 1" adjustment for a reading of
100 pF.
(b) Depress tpe red button on the standard capacitor,
reducing its 0 to 3, and adjust the rear-panel "CAL 2"
control so that the meter again reads 100 pF.
(c) Release the switch. If the instrument still reads
100 pF, calibration is complete. If not, repeat
Steps a, b, and c upti1 the instrument reads 100
pF for both tests.
3.10.3 calibration Check of Model 7lA with a Standard other
Than the Model 71-1A
The use of a conventional three-terminal capaGitance standard
for low Q calibration is not recommended owing to the un-
certainty of the capacitance ot the resistor which must be
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7lA