Page 84 - Understanding Automotive Electronics

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ELECTRONICS FUNDAMENTALS 3

Electronics Fundamentals

This chapter is for the reader who has little knowledge of electronics. It is
intended to provide an overview of the subject so that discussions in later
chapters about the operation and use of automotive electronics control systems
will be easier to understand.
The chapter discusses electronic devices and circuits having applications
in electronic automotive instrumentation and control systems. Topics include
semiconductor devices, analog circuits, digital circuits, and fundamentals of
integrated circuits.
SEMICONDUCTOR DEVICES

Semiconductor (or solid-state) devices are basic building blocks for
electronic circuits. Semiconductor devices are commonly called solid-state
devices because they are made from a solid material. This material in pure form
is neither a good conductor nor a good insulator. Therefore, this material (also
called semiconductor material) and devices made from it are solid-state
semiconductor devices.
There are many types of semiconductor devices, but transistors and
diodes are two of the most important in automotive electronics. Furthermore,
these devices are the fundamental elements used to construct nearly all modern
integrated circuits. Therefore, the discussion of semiconductor devices will be
centered on these two.
Semiconductor devices The earliest transistors were made from germanium, but today silicon is
are made from silicon or by far the most commonly used semiconductor material for making diodes,
germanium that is pur- transistors, and other semiconductor devices. Semiconductor material is made
posely contaminated to conduct better by diffusing an impurity into it. Boron and phosphorus often
with impurities that are used as impurity source materials to alter the conductivity of silicon. When
change the conductivity boron is used, the semiconductor material becomes a so-called p-type
of the material. Transis- semiconductor. When phosphorus is used, the semiconductor material
tors are semiconductor becomes an n-type semiconductor. It is not necessary for the purposes of this
devices that are used as book to understand the differences between p-type and n-type semiconductors.
active devices in elec- However, the interested reader can consult any of the standard introductory
tronic circuits. references on the theory of semiconductor devices for further information.
Semiconductor devices such as diodes and transistors are quite different
from common linear components such as resistors, capacitors, inductors, and
transformers. The following discussion presents an explanation of the operation
of these devices.

UNDERSTANDING AUTOMOTIVE ELECTRONICS 71