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OPERATION
-
Chassis
Ground
Warning : Do not Exceed Maximum
Voltage Levels Shown
Figure 2-3. Triax Connector
Configuration
WARNING
Do
not exceed 200V
between SIGNAL and
GUARD, or between
SIGNAL and chassis
ground, or GUARD and chassis ground.
The Model 7072 has 12 columns that are labelled 1 through
12, as well as eight rows, A through H. Rows A and B are
labelled LOW I and are intended for low-current
measure-
ments. Rows G and H are labelled CV and are designed
for capacitance-voltage
measurements.
Rows C through F
are general purpose rows that can be used for ordinary
voltage, current,
or resistance measurements.
2.5.2 Recommended
Cables and Adapters
Table 2-l summarizes the cables and adapters recommend-
ed for use with the Model 7072. Equivalent
user-supplied
items may be substituted
as long as they are of sufficient
quality (low offset current, high leakage resistance). Using
substandard cables and adapters may degrade the integrity
of the measurements
made using the matrix card. See
paragraph 2.7 for a discussion of measurement considera-
tions.
Table 2-1. Recommended
Cables and Adapters
Description
6171
3-slot male to 2-lug
female triax.
6011 2-slot triax to alliga-
tor cable*
7078-TRX-3, 7078TRX-10
triax cables
7078.TRX-T triax tee
adapter
7078TRX-BNC
triax to
BNC adapter
7025 unterminated
triax
(2
slot)
Guarded
adapter
(6167**)
Applications
Connect 2.slot triax cable
to 7072
7072 input/output
connections
7072 input/output
connections
Daisy chain 7072 columns
or rows
Connect BNC cables to
7072
For custom 7072
connections
Guarded
current source
*Model 6171 adapter required to connect these cables to
Model 7072
**6167 requires modification
by disconnecting
input LO
internally.
2.5.3 Triaxial to Banana
Plug Adapter
Preparation
For instruments that use banana jacks, a special 3-slot hiax-
to-single
banana plug must be prepared,
as discussed
below. This special cable can be prepared as outlined below
using the parts listed in Table 2-2. Note that you can use
either an unterminated
triax cable, or cut a dual-connector
cable (7L?78-TRX-10) in half to construct two cables. The steps
for the procedure
below are shown in Figure 2-4.
1. Using a knife, cut and strip back the outer insulation
about 1% inches.
2. Remove the outer insulation,
then cut away the outer
shield back as far as the insulation
is stripped.
3. Carefully strip away the insulation
over the inner shield
one inch, then cut the inner shield off even with the
stripped
insulation.
4. Strip the inner conductor % inch, then twist the strands
together.
5. Unscrew the cover from a banana plug, then slide the
cover over the center conductor
of the t&xx cable.
6. Insert the stripped center conductor
through
the hole
in the body of the banana plug, then wrap the wire
around the plug body.
7. Screw on the plastic cover, and make certain the wire
is secure by gently pulling
on the plug.
2-4
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