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TRANSISTOR RUGGEDNESS | Up
Neets Module 19-The Technicians Handbook | Next
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1-35
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Connect a ground between the test equipment and circuit under test.
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Do not exceed the maximum allowable voltages for circuit components and transistors.
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Ohmmeter ranges that require more than one milliampere should not be used for testing
transistors.
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Battery eliminators should not be used to furnish power for transistorized equipment. They have
poor voltage regulation.
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The heat applied to a transistor, when soldered connections are required, should be kept to a
minimum by the use of low-wattage soldering irons and heat shunts or heat sinks.
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When replacing transistors, never pry them from the printed circuit board.
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Check all circuits for defects before replacing transistors.
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Remove power from the equipment prior to replacing a transistor.
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Use extreme care when using test probes on a transistorized circuit. It is easy to short across
adjacent terminals with conventional probes. Try insulating the probe tips and leaving a very
short section of the point exposed.
You can find more about transistors in NEETS, Module 7, Introduction to Solid-State Devices and
Power Supplies.
Vacuum Tubes
The characteristics of a vacuum tube are measured by two factors: AMPLIFICATION FACTOR,
mu (µ), and TRANSCONDUCTANCE (gm).
Formula for amplification factor:
Formula for transconductance (gm) is:
Information on vacuum tubes can be found in NEETS, Module 6, Introduction to Electronic
Emission, Tubes, and Power Supplies.
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