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PART IV. SINGLE-LIMIT TESTING
3.8
GENERAL.
The single-limit testing mode of operation can be used for testing
and sorting operations of capacitors, inductors, and semiconductor devices during
production testing, incoming inspection, quality assurance, and similar applications.
Normally, either a test jig or coaxial test leads are used to connect specimens to the
Model 75D to facilitate testing.
If feasible, however, test specimens may be connected
directly to the front-panel terminals.
3.8.1
SINGLE-LIMIT CAPACITANCE TEST.
The Model 75D is used in the following
procedure to perform go/no-go tests of capacitive specimens that are to be sorted.
In
this test,the Model 75D compares the capacitance of each specimen with either an upper-
limit value or a lower-limit value that has been programmed into the instrument,and a
go or no-go readout indicates the test result.
Although the Model 75D can be programmed
for only one limit, dual-limit tests may be performed by repeating the procedure for the
other limit.
(If the ground-plane adapter is being used, disregard Step b, below.)
a. Check that the initial settings on the front pane! of the Model 75D are in
accordance with Table 4.
b. If test specimens are to be connected directly to the Model 75D, remove the
terminal shield from the TEST binding posts.
If coaxial test leads or a test
jig is to be used, connect the item to the REMOTE TEST coaxial connectors.
(Disregard this step if the ground-plane adapter is being used.)
c. Determine the required limit value and set the MULTIPLY C, DIVIDE
G/MULTIPLY R, and C/L switches to the positions indicated in the chart
below.
(Do not adjust the CONDUCTANCE control.) If the tolerance is in
percentage, convert the percentage tolerance to capacitance values and
algebraically add the required tolerance to the nominal value of the
specimen.
(For example, a * 5% tolerance for a nominal 100 pF capacitor
converts to 5 pF and becomes 105 pF for the upper limit and 95 pF for the
lower limit.)
TOLERANCE LIMIT
(pF)
MULTIPLY C
SWITCH
DIVIDE <3/
MULTIPLY R
SWITCH
C/L
SWITCH
CONDUCTANCE
CONTROL
G-SCALE
1 00 to 1000
1
1
L
+1000
10 to 100
0.1
1
C
-100*
1 to 10
0.01
10
C
-100*
0.1 to 1
0. 001
100
C
-100*
0 to 0.1
0.0001
1000
C
-100*
*Tenth (red) subdivision on G-scale to the left of zero.
75D
b-370
32
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