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
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.