Chapter 1
Introduction to Electronics
1.1 DEFINITION OF ELECTRONICS
ELECTRONICS comes from the word electron, which is one of the basic particles present
in all materials having a negative electric charge. ELECTRONICS is defined as the branch of
science and technology that deals with the control of free electrons and other charge carriers
flowing in vacuum, gas and semiconductor materials. Note that the field of science and technology
that deals with the flow of electrons in metals is not considered as electronics engineering, it is
basically electrical engineering. However, Electrical and Electronics engineering are related since
both share common fundamental principles regarding of electricity and magnetism.
1.2 HISTORY OF ELECTRONICS
The history of electronics is divided into two major periods of time, the vacuum tube era
and the transistor era. The first era began with the invention of vacuum tubes during the first half
of 20th century and the second era started with the invention of the transistor during the latter half
of the 20th century up to present.
VACUUM TUBE ERA
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History shows that the development of Electronics began in 1883 when Thomas A. Edison
discovered how the conduction of electric current takes place in a vacuum. In his
experiment, he inserted a metal plate near the filament of his incandescent light bulb, that
are both enclosed in a vacuum. Applying a positive voltage to the plate with respect to the
filament, Edison observed that current flowed through the light bulb. However, reversing
the polarity of the voltage across the plate and the filament, no current was produced. The
current was actually due to the flow of electrons emitted by the hot filament but during that
time electron theory was not yet known, and this electrical phenomenon was simply called
Edison Effect.
Figure 1.1 Thomas Alva Edison (February 11, 1847 – October 18, 1931) and his light bulb
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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Hendrik Antoon Lorentz (July 18, 1853 – February 4, 1928) postulated
the existence of a discrete charge called electron in 1895.
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Sir Joseph John Thomson (December 18, 1856 – August 30, 1940) did
three experiments to prove the existence of electron in 1897.
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Sir John Ambrose Fleming (November 29, 1949 – April 18, 1945)
adapted the Edison Effect to develop the vacuum tube diode (valve) in 1904. Vacuum tube
diode was used to rectify or detect radio signals.
Figure 1.2 Vacuum tube diode (Fleming valve)
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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Dr. Lee de Forest (August 26, 1873 – June 30, 1961) invented the
vacuum tube triode (audion) in 1906. Vacuum tube triode was used to amplify electrical
signal.
Figure 1.3 Vacuum tube triode (audion)
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Walter Schottky (July 23, 1886 – March 4, 1976) invented the vacuum
tube tetrode in 1919 to overcome the undesirable effect of inter-electrode capacitance
existing in a triode at high frequency operation.
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In 1926, Benjamin D. H. Tellegen developed the pentode to overcome the effect of
secondary emission happening in a vacuum tube tetrode.
Figure 1.4 Schematic symbols of vacuum tube tetrode and vacuum tube pentode
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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The discovery of vacuum tubes made radio broadcasting, TV broadcasting and
telecommunication progress rapidly.
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Vacuum tubes were also utilized in the world’s first electronic computer named ENIAC
(Electronic Numerical Integrator and Calculator) used during World War II. ENIAC had
18,000 vacuum tubes, weighed more than 30 tons and occupied an area of 1,500 square
feet. It was built at the University of Pennsylvania's Moore School of Electrical
Engineering.
Figure 1.5 General view of ENIAC
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In 1948, George Philbrick built the first vacuum tube op-amp used in analog computer in
performing mathematical operations such as addition, subtraction, multiplication,
integration, differentiation and logarithms.
TRANSISTOR ERA
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In December 1947, John Bardeen and Walter Brattain of the Bell Telephone Laboratories
invented the first germanium point-contact transistor, a solid-state semiconductor device
capable of amplifying electrical signals.
Figure 1.6 First Germanium point contact transistor
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In January 1948, William Shockley created the first junction transistor, a solid-state
device similar to what we now call a junction field-effect transistor.
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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Figure 1.7 First Junction Transistor
A transistor can perform all functions of a vacuum tube triode but it has a smaller size, lower
power consumption and lesser heat losses.
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In 1959, the electronic industry once again progressed with the invention of the Integrated
Circuit (IC) by Jack Kilby of Texas Instruments and Dr. Robert Noyce of Fairchild
Semiconductor. This technology combines transistors, diodes, resistors and capacitors on a
single semiconductor substrate, thus, reducing the size of most electronics circuits.
Figure 1.8 Texas instrument’s first IC
Figure 1.9 Modern Integrated Circuit
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In 1963, Fairchild introduced the first IC op-amp, µA702.
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In 1971, one of the important developments in Integrated Circuit happened when M. E.
Hoff of Intel Corporation developed the microprocessor, an Integrated Circuit containing
all the components of a computer’s central processing unit. With this new technology,
advanced computer systems and electronic equipment were made possible.
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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1.3 FIELDS OF ELECTRONICS
There are different fields of electronics that people encounter in their everyday life. One of
these fields is COMMUNICATION ELECTRONICS. This includes Amplitude Modulation (AM) /
Frequency Modulation (FM) radio and television (TV) that makes people aware of the news and
current events happening around the world. It also includes telephone systems and Internet
services that allow people to keep in touch with each other.
Figure 1.10 Applications in the field of Communication Electronics
Advance computer system, bar code readers/scanners and digital calculators are
applications in the field of DIGITAL ELECTRONICS. This field of electronics involves electronic
systems that operate with pulses of voltage or current. Absence of pulse indicates OFF state (logic
0) while presence of pulse indicates ON state (logic 1).
Figure 1.11 Applications in the field of Digital Electronics
In these days, electronics is also use in cars! Computer-controlled fuel injection and antilock brake systems and all other automated features in cars are applications in the field of
AUTOMOTIVE ELECTRONICS. This field also includes electronic equipment used in monitoring
and testing car performance and status.
Figure 1.12 Applications in the field of Automotive Electronics
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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The field of INDUSTRIAL ELECTRONICS involves different electronic system and devices
used in the office, factory and industrial set-up.
Figure 1.13 Applications in the field of Industrial Electronics
MEDICAL ELECTRONICS integrates electronics in the field of medicine. Nowadays,
medical equipment like Ultrasound, CTScan and Electrocardiograph are computerized and
electronically controlled. These help those in medical profession analyze and treat their patients
faster and more accurately.
Figure 1.14 Applications of Medical Electronics
1.4 ELECTRONIC COMPONENTS
Electronic circuits like amplifiers, power supplies and digital logic circuits are implemented
using active and passive components. Vacuum tubes, diodes, transistors and integrated circuits are
examples of active electronic components that are capable of amplifying or controlling voltage and
current. Resistors, Capacitors and Inductors are considered passive components.
Figure 1.15 Passive electronic components
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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Figure 1.16 Active electronic components
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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REVIEW QUESTIONS
MULTIPLE CHOICE. Shade the letter corresponding to the correct answer.
1.1 Electronics deal with the control of the flow of electrons in ______.
(a) Vacuum
(c) Semiconductor
(b) Gas
(d) all of the above
1.2 Which of these is not an application of electronics?
(a) AM/FM radio receiver
(c) Ultrasound & ECG
(b) Computers & digital calculator
(d) AC motors and generators
1.3 Who invented the world’s first microprocessor?
(a) Dr. Lee de Forest
(c) J.A Fleming
(b) M.E. Hoff
(d) J. Kilby
1.4 A vacuum tube triode is also known as _______.
(a) Audion
(c) Valve
(b) Controller
(d) Rectifier
1.5 The advantage of transistor over vacuum tube triode is/are
(a) its small size
(c) low power consumption
(b) less heat losses
(d) all of the above
1.6 Which of the following constitutes an active electronic component?
(a) Semiconductor device
(c) Resistors
(b) Capacitors
(d) Inductors
1.7 The first solid-state semiconductor device capable of amplifying electrical signal was a ___.
(a) Germanium point contact transistor
(c) Junction Transistor
(b) Operational Amplifier
(d) Triode
1.8 Who invented the vacuum tube diode?
(a) Dr. Lee de Forest
(c) J.A Fleming
(b) Thomas A. Edison
(d) J. Kilby
1.9 The world’s first electronic computer named
(a) Electronic Numerical Integrator and Differentiator
(b) Electronic Numeric Integrator and Computer
(c) Electronic Numerical Integrator and Calculator
(d) Electronic Number Integrator and Computer
1.10 Walter Schottky invented the __________ to overcome the undesirable effect of interelectrode capacitance existing in a triode at high frequency operation.
(a) Diode
(c) Tetrode
(b) Vacuum-tube Op-amp
(d) Pentode
1.11 This field of electronics involves electronic systems that operate with pulses of voltage or
current.
(a) Communication Electronics
(c) Industrial Electronics
(b) Digital Electronics
(d) Automotive Electronics
1.12 The person who inserted a third element called the grid between the plate and filament of a
Fleming valve in 1906 was
(a) Thomas Edison
(c) J.A Fleming
(b) Albert Einstein
(d) Dr. Lee De Forest
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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REFERENCES
Books
[1] Grob, B. Basic Electronics. New York: McGraw-Hill, 1984.
[2] Millman, J. and Grabel, A. Microelectronics. New York: McGraw-Hill, 1987.
[3] McGraw-Hill Encyclopedia of Electronics and Computers, 2nd Ed. New York: McGraw-Hill,
1988.
Websites
[4] http://www.library.upenn.edu/special/gallery/mauchly/jwm0-1.html
[5] http://www.leedeforest.org
[6] http://chem.ch.huji.ac.il/~eugeniik/history/fleming.htm
[7] http://www.pbs.org/transistor
Chapter 1 - Introduction to Electronics
Montesines-Nagayo, A. & Sybingco, E., A Study Guide in Electronics Circuit Analysis (2nd Edition)
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