Boonton Electronics 71A, 71AR - Connection for Inductance

3.11 Inductance Measurements
3.11.1 General
with the "L/C" selector in the "L" position the Models 7lA
and 7lAR measure two-terminal inductance. It will be noted
that with the "L" position, the normal resting place of
the indicator, with no specimen connected to the "INDUCTANCE"
terminals, is at the extreme right, above full scale; it
moves down scale only when a specimen of measureable value
for that range is placed across the terminals.
3.12 Connections for Inductance Measurement
Ipductance should be connected directly to the "INDUCTANCE"
terminals. Use of connecting leads will introduce errors of
measurement as shown in Fig. 3.3.
3.13 Inductance Zero Check
The Model 71A can be quickly checked for L zero by placing a
short length of #22 copper wire tightly across the "INDUCTANCE"
terminals, with the "RANGE" selector set at l~. The reading
should be three-quarters of a minor scale division above zero.
If not, the "L ZERO" control (center adjustment on the left
side of the instrument) should be adjusted for this reading.
(NOTE: The controls immediately above and below the "L ZERO"
control are factory adjustments and their settings should not
be disturbed.)
Once adjusted as described above, the Model 7lA is properly
set for all inductance ranges.
IMPORTANT NOTE
The "1000 pF ZERO" control should be properly set
(see paragraph 3.4) before checking the inductance
zero position. The "1000 pF ZERO" has a direct in-
fluence on inductance readings and once set~ should
not be disturbed during the course of measurement.
3-17
7lA
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