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Introduction to Transistors
A.
Bhatia
Overview
A transistor is a small
electronic device that amplifies a signal or can turn electricity on or off.
Invented in 1948 at Bell Labs, transistors have become the key ingredient of all
digital circuits, including computers.
A transistor consists of
three layers of silicon or germanium semiconductor material. Impurities are
added to each layer to create a specific electrical positive or negative charged
behavior: There are essentially two basic types of point-contact transistors,
the NPN transistor and the PNP transistor, where the N and P stand for negative
and positive, respectively. The only difference between the two is the
arrangement of bias voltages.
To understand how a
transistor works, you have to understand how semiconductors react to an electric
potential. Some semiconductors will be N-type, or negative, which means that
free electrons in the material drift from a negative electrode (of, say, a
battery it's connected to) toward the positive. Other semiconductors will be
P-type, in which case the electrons fill "holes" in the atomic electron shells,
meaning that it behaves as if a positive particle is moving from the positive
electrode to the negative electrode. The type is determined by the atomic
structure of the specific semiconductor material.
This
4-hr course provides a basic understanding of the
physical concepts needed to understand the semiconductor fundamentals of
semiconductor devices. The course is based entirely on Naval Education and
Training Materials (NAVEDTRA 14178), Electricity
and Electronic Training Series; Module-7 and covers Chapter 2 titled
"Transistors".
The student must take a multiple-choice quiz
consisting of twenty (20) questions at the end of this course to obtain PDH
credits.
Specific Knowledge or Skill Attained
At the conclusion of this course, the reader will
be able to:
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Define the term
"transistor" and give a brief description of its construction and operation
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Explain how the
transistor can be used to amplify a signal
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Name the four classes of
amplifiers and give an explanation for each
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List the three different
transistor circuit configurations and explain their operation
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Identify the different
types of transistors by their symbology and alphanumerical designations
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List the precautions to
be taken when working with transistors and describe ways to test them
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Understand how
integrated circuits are constructed and the advantages they offer over
conventional transistor circuits
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Name the two types of
circuit boards
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State the purpose and
function of modular circuitry
Course
Click on the following PDF attachment and review the document
prior to taking
a quiz for credit.
Transistors (669 KB)
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credit. Click on the link below.
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