Introduction to
Electronic Engineering
Analog Electronics
,Contents Page No.
1. Introduction 3
2. Semiconductors and their Conductivity 8
3. The PN Junction Diode 23
4. Transistors 37
Page 2 of 110
,1. Introduction
The general term Electronics encompass a wide range of topics that
include audio systems, computers, communication systems,
instrumentation and automatic control systems. All these different areas
in electronics have as a common theme the use of electronic devices such
as transistors, diodes and integrated circuits.
To study electronics we must also study semiconductor materials because
all modern electronic devices are made with semiconductor material, of
which Silicon (Si) is the most widely used. Semiconductors have special
electrical conductivity properties, most important and interesting of
which is that their electrical conductivity is due to negatively charged
electrons and positively charged holes (an electron vacancy). The
conductivity of a pure semiconductor such as Si can be controlled by
adding impurities which provides a way to design and develop different
electronic devices.
Of all the electronic devices that are abundant in our modern
environment, by far the most widely used device is the transistor. The
transistor can be said to be the fundamental building block of electronics
and used in very diverse technologies such as amplifiers and other
components in audio and acoustic engineering, power amplifiers in
telecommunications and control systems and of course digital computers
where the transistors perform all the data storage, retrieval and processing
actions. Most engineering applications will invariably involve devices
which have transistors at their heart so a reasonable knowledge of
transistors and their applications is important for students in any
engineering field.
Page 3 of 110
, Analog and Digital Waveforms
As a preliminary, we first look at some fundamental aspects you will
encounter in this text.
In a x-y coordinate system, electronic waveforms are normally
represented as the variation of voltage (y- axis) as a function of time (x-
axis). Sometimes the y- axis can represent current or power instead of
voltage.
The voltage versus time waveforms, commonly called signals, that we
encounter in Electronics can be broadly categorized as
a) Analog waveforms and b) Digital waveforms
An analog waveform is characterized by a smooth continuous voltage
distribution e(t) with respect to time t. An example of this type of
waveform is a sinusoidal signal e(t) = A sin ωt where A is amplitude and
ω = 2πf is the angular or circular frequency in units of radians, and f is
frequency in units of Hz defined below.
By contrast a digital waveform has only two voltage levels (V and 0) with
respect to time as shown below. In the digital waveform V can also
represent a HIGH level or 1 and 0 a LOW level or 0.
Page 4 of 110
Electronic Engineering
Analog Electronics
,Contents Page No.
1. Introduction 3
2. Semiconductors and their Conductivity 8
3. The PN Junction Diode 23
4. Transistors 37
Page 2 of 110
,1. Introduction
The general term Electronics encompass a wide range of topics that
include audio systems, computers, communication systems,
instrumentation and automatic control systems. All these different areas
in electronics have as a common theme the use of electronic devices such
as transistors, diodes and integrated circuits.
To study electronics we must also study semiconductor materials because
all modern electronic devices are made with semiconductor material, of
which Silicon (Si) is the most widely used. Semiconductors have special
electrical conductivity properties, most important and interesting of
which is that their electrical conductivity is due to negatively charged
electrons and positively charged holes (an electron vacancy). The
conductivity of a pure semiconductor such as Si can be controlled by
adding impurities which provides a way to design and develop different
electronic devices.
Of all the electronic devices that are abundant in our modern
environment, by far the most widely used device is the transistor. The
transistor can be said to be the fundamental building block of electronics
and used in very diverse technologies such as amplifiers and other
components in audio and acoustic engineering, power amplifiers in
telecommunications and control systems and of course digital computers
where the transistors perform all the data storage, retrieval and processing
actions. Most engineering applications will invariably involve devices
which have transistors at their heart so a reasonable knowledge of
transistors and their applications is important for students in any
engineering field.
Page 3 of 110
, Analog and Digital Waveforms
As a preliminary, we first look at some fundamental aspects you will
encounter in this text.
In a x-y coordinate system, electronic waveforms are normally
represented as the variation of voltage (y- axis) as a function of time (x-
axis). Sometimes the y- axis can represent current or power instead of
voltage.
The voltage versus time waveforms, commonly called signals, that we
encounter in Electronics can be broadly categorized as
a) Analog waveforms and b) Digital waveforms
An analog waveform is characterized by a smooth continuous voltage
distribution e(t) with respect to time t. An example of this type of
waveform is a sinusoidal signal e(t) = A sin ωt where A is amplitude and
ω = 2πf is the angular or circular frequency in units of radians, and f is
frequency in units of Hz defined below.
By contrast a digital waveform has only two voltage levels (V and 0) with
respect to time as shown below. In the digital waveform V can also
represent a HIGH level or 1 and 0 a LOW level or 0.
Page 4 of 110
