7.
By using a transistor tester and a scope you can test transistors in the same
manner as you test diodes. To test a transistor connect the transistor tester to
the scope, and adjust the scope as follows:
a. Connect the vertical input probe of the scope to the Y input terminal of
the tester, the horizontal input probe of the scope to the X input terminal of the
tester, and the common probe of the scope to the reference terminal on the tester.
b. Short E to B on the tester, and adjust the horizontal gain control on the
scope until you get a 4-cm horizontal display on the scope.
c. Short E to C on the tester, and adjust the signal voltage until you get a
2-cm vertical display.
d. Connect a transistor to the tester (emitter to E, base to B, and collector
to C).
8.
Determine the condition of the transistor under testing by comparing your
trace with the traces illustrated in Figures 3-18, 3-19, and 3-20. As in testing
diodes, you can test known good transistors and make your own trace patterns to
compare with other transistors.
Figure 3-19. Oscilloscope traces of
Figure 3-18. Oscilloscope traces of
NPN transistors
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