Typical Test Fixture Connections; Figure - Keithley 7174A Instruction Manual

2.5.6 Typical test fixture connections
Typically, one or more test fixtures will be connected to
desired columns of the Model 7174A. Typically, the test fix-
tures will be equipped with card-edge connectors with wires
soldered to them. In some cases, the test fixture will be
equipped with triax connectors; for those types, Keithley
Model 7078-TRX-(3, 10, or 20) cables can be used, as shown
in Figure 2-12.
WARNING
Do not use BNC cables and adapters in
cases where hazardous voltages from
guard sources could be present on the
BNC cable shields.
KE ITH LE Y 7174A
8 x 12 L OW
CU R R E NT MATRIX
S IGNAL
COL UMNS
200V P K 200V P K
GUARD
200V PK
ROWS
1
A
2
B
3
C
4
D
5
6
7
8
E
9
F
10
G
11
H
12
!
WAR NING:
TIGHTE N MOUNTING S CR E WS
TO E NS UR E P R OP E R
CHAS S IS GR OUND
7174A Matrix Card

Figure 2-12

Typical test fixture connections
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Internally, the test fixture should be wired as shown in the
equivalent circuit of Figure 2-13. SIGNAL should be con-
nected to the probe or other device contact points, while
GUARD should be carried through as close to the device as
possible. If coaxial probes are to be used, connect GUARD
to the probe shield if the probe shield is insulated from the
fixture shield.
Usually, the chassis ground terminal of the triax connector
will automatically make contact with the fixture shield by
virtue of the mounting method. However, ground integrity
should be checked to ensure continued protection against
hazardous guard voltages.
3 - Lug Female
Triax Connectors
Test Fixture
(or run cables through strain
reliefs and connect internally)
Note: Teflon -insulated connectors
recommended for specified
performance.
Warning: Do not use BNC connectors
to avoid possible shock
hazard.
Operation
®
2-17