Sencore TF151 - Safety Precautions

Safety Precautions
When testing electronic equipment, there is always a danger present. Unexpected
high voltages can be present at unusual l ocations in defective equipment. The tech-
nician should become familiar with the device that he is working on and observe the
following
precautions.
1. An isolation transformer should always be used on equipment having the chassis
tied to one side of the AC power line.
Z. When making test lead connections to high voltage points, remove the power. If
this cannot be done, be sure to avoid contact with other equipment or metal ob-
jects . Place one hand in your pocket as a safety precaution and stand on an in-
sulated floor to reduce the possibility of shock .
3.
Discharge filter capacitors before connecting test leads to them. Capacitors can
store a charge that could be dangerous to the technician.
4. Be sure your equipment is in good order. Broken or frayed test leads can be
extremely dangerous and can expose the technician to dangerous potentials.
s. Remove the test leads immediately after the test has been completed to reduce
the possibility of shock.
6. Do not work alone when working on hazardous circuits. Always have another
person close by in case of accid ent. Remember, even a minor shock can be the
cause of a more serious accident, such as falling against the equipment, or coming
in contact with higher voltages.
TABLE OF CONTENTS
PAGE
Description ..
4
Specifications
4
Common transistor Terminolgy .
5
Controls on the TF1Sl ..... .
5
Using the Sencore FET and Transistor Reference Book.
6
Testing Regular Transistors (Bi-polar) .
8
Regular Transistor Trouble Chart ...
10
Checking Regular Transistors for Leakage (ICBO)
II
Testing Field Effect Transistors ........ .
II
Depletion and Enhancement modes in Field Effect Transistors
12
Measuring Gm of the Field Effect Transistor In or Out of Circuit.
12
Field Effect Tra nsistor Trouble Chart . . . . . . . . . . .
14
Checking Gate Leakage (IGSS) of Field Effect Transistors. 14
Zero Bias Drain Current. . ..... 15
Dual Gate Field Effect Transistors 16
Dual Field Effect Transistors . . .
16
2