10
Electronics
Quarter III – Module 2, Lesson 1
Signal Control, Components and Applications
of Radios
Electronics – Grade 10
Self-Learning Module
First Edition, 2020
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Published by the Department of Education – Regional Office VIII
Regional Director: Ramir B. Uytico EdD, CESO IV
Assistant Regional Director: Arnulfo M. Balane, CESO V
Development Team of the Module
Writer: Menchu A. Canlas
Language Editors: Henry A. Singcol
Content Editors: Girlie E. Diaz
Illustrators: Name
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Management Team:
Rosemarie M. Guino EdD, OIC – Chief, CLMD
Ryan R. Tiu EdD, EPS, CLMD – Science
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Lucel C. Roa, Chief, CID
Rosario M. Canlas, EPS, CID – Science
Francisci Bayon-on. EPS, CID - LRMS
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Introductory Message
This Self-Learning Module (SLM) is prepared so that you, our dear learners,
can continue your studies and learn while at home.
Activities, questions,
directions, exercises, and discussions are carefully stated for you to understand
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learning. Answer keys are provided for each activity and test. We trust that you will
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In addition to the material in the main text, Notes to the Teacher are also
provided to our facilitators and parents for strategies and reminders on how they
can best help you on your home-based learning.
Please use this module with care. Do not put unnecessary marks on any
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If you have any questions in using this SLM or any difficulty in answering
the tasks in this module, do not hesitate to consult your teacher or facilitator.
Thank you.
Notes to the Teacher
This contain helpful tips or strategies that will help you in guiding the
learners.
ii
For the learner:
Welcome to the Research 7 Self – Learning Module 1on (Lesson Title)!
The hand is one of the most symbolized part of the human body. It is often used to
depict skill, action, and purpose. Through our hands we may learn, create, and
accomplish. Hence, the hand in this learning resource signifies that you as a
learner is capable and empowered to successfully achieve the relevant
competencies and skills at your own pace and time. Your academic success lies in
your own hands!
This module was designed to provide you with fun and meaningful opportunities
for guided and independent learning at your own pace and time. You will be
enabled to process the contents of the learning resource while being an active
learner.
This module has the following parts and corresponding icons:
Explore
Learn
What’s More
Apply
Assess
Answer Key
Reflect
This will give you an idea of the skills or
competencies you are expected to learn in the
module. A brief drill or review to help you link
the current lesson with the previous one. The
new lesson will also be introduced to you in
various ways such as a story, a song, a poem, a
problem opener, an activity, or a situation.
This section provides a brief discussion of the
lesson. This aims to help you discover and
understand new concepts and skills.
This comprises activities for independent
practice to solidify your understanding and
skills of the topic. You may check the answers
to the exercises using the Answer Key at the
end of the module.
This
includes
questions
or
blank
sentence/paragraph to be filled into process
what you learned from the lesson.
This is a task which aims to evaluate your level
of
mastery
in
achieving
the
learning
competency.
This contains answers to all activities in the
module.
This contains the learner’s reflection. Learners
are encouraged to think about the lessons
particularly the parts that went well (they have
understood) and the parts that were weak (they
have difficulty) and write about it briefly.
Learners can share their thoughts and feeling
about the lessons.
iii
At the end of this module you will also find:
References
This is a list of all sources used in
developing this module.
The following are some reminders in using this module:
1. Use the module with care. Do not put unnecessary mark/s on any part of
the module. Use a separate sheet of paper in answering the exercises.
2. Read the instruction carefully before doing each task.
3. Observe honesty and integrity in doing the tasks and checking your
answers.
4. Finish the task at hand before proceeding to the next.
5. Return this module to your teacher/facilitator once you are through with it.
If you encounter any difficulty in answering the tasks in this module, do not
hesitate to consult your teacher or facilitator. Always bear in mind that you are
not alone.
We hope that through this material, you will experience meaningful learning
and gain deep understanding of the relevant competencies. You can do it!
iv
Explore
Introduction:
Radio waves are a type of electromagnetic radiation with wavelengths in
the electromagnetic
spectrum longer
than infrared light.
Radio
waves
have frequencies as high as 300 gigahertz (GHz) to as low as 30 hertz (Hz).[1] At 300
GHz, the corresponding wavelength is 1 mm (shorter than a grain of rice); at 30 Hz
the corresponding wavelength is 10,000 km (longer than the radius of the Earth).
Like all other electromagnetic waves, radio waves travel at the speed of light in
vacuum (and close to the speed of light in the Earth's atmosphere, which acts as
the transmission media for the vast majority of terrestrial use). Radio waves are
generated
by charged
particles undergoing acceleration,
such
as
timevarying electric currents.[2] Naturally occurring radio waves are emitted
by lightning and astronomical objects.
Radio waves are generated artificially by transmitters and received by radio
receivers, using antennas. Radio waves are very widely used in modern technology
for
fixed
and
mobile radio
communication, broadcasting, radar and radio
navigation systems, communications satellites, wireless computer networks and
many other applications. Different frequencies of radio waves have different
propagation
characteristics
in
the
Earth's
atmosphere;
long
waves
can diffract around obstacles like mountains and follow the contour of the earth
(ground waves), shorter waves can reflect off the ionosphere and return to earth
beyond the horizon (skywaves), while much shorter wavelengths bend or diffract
very little and travel on a line of sight, so their propagation distances are limited to
the visual horizon.
Radio waves are all around us and play an important role in our everyday lives.
Radio waves keep us connected with one another. With radio waves, text and talk
on the telephone are possible.
After going through this module, you are expected to:
1. define radio waves;
2. illustrate and discuss the electromagnetic spectrum;
3. analyze the electronics hardware and process of transmitting and receiving
radio waves;
Q2_STE_Electronics_ Module 2-3
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Learn
Radio waves
Radio waves are waves of energy that are found on the electronic spectrum.
Radio waves were proven by Heinrich Hertz in 1887. Radio waves are
measured in hertz after Heinrich Hertz, and most often known and classified
as megahertz and gigahertz. Like all other electromagnetic waves, radio waves
travel at the speed of light in vacuum at the same speed (and close to the speed of
light in the Earth's atmosphere, which acts as the transmission media for the vast
majority
of
naturally
occurring
radio
waves
are
emitted
by lightning and astronomical objects.
The Electromagnetic Spectrum
The electromagnetic (EM) spectrum is
the range of all types of EM radiation. Radiation
is energy that travels and spreads out as it goes
– the visible light that comes from a lamp in
your house and the radio waves that come from
a radio station are two types of electromagnetic
radiation. Microwave, infrared light, ultraviolet
light, X-rays and gamma rays are the other
types of electromagnetic radiation.
You know more about the electromagnetic
spectrum than you may think. The image at the
left shows where you might encounter each
portion of the EM spectrum in your day-to-day
life.
The electromagnetic spectrum from
lowest energy/longest wavelength (at the top) to
highest energy/shortest wavelength (at the
bottom).)
Radio: Your radio captures radio waves emitted
by radio stations, bringing your favorite tunes.
Radio waves are also emitted by stars and
gases in space.
Microwave: Microwave radiation will cook your
popcorn in just a few minutes, but is also used
by astronomers to learn about the structure of
nearby galaxies.
https://imagine.nasa.gov/images/scien
ce/EM_spectrum_full.jpg
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Infrared: Night vision goggles pick up the infrared light emitted by our skin and
objects with heat. In space, infrared light helps us map the dust between
stars.
Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible
light
Ultraviolet: Ultraviolet radiation is emitted by the Sun and are the reason skin
tans and burns. "Hot" objects in space emit UV radiation as well.
X-ray: A dentist uses X-rays to image your teeth, and airport security uses them to
see through your bag. Hot gases in the universe also emit X-rays.
Gamma ray: Doctors use gamma-ray imaging to see inside your body. The biggest
gamma-ray generator of all is the Universe.
Radio Electronics: Transmitters and Receivers
Radio waves are generated artificially by transmitters and received by radio
receivers, using antennas. Radio waves are very widely used in modern technology
for
fixed
and
mobile radio
communication, broadcasting, radar and radio
navigation systems, communications satellites, wireless computer networks and
many other applications. Different frequencies of radio waves have different
propagation
characteristics
in
the
Earth's
atmosphere;
long
waves
can diffract around obstacles like mountains and follow the contour of the earth
(ground waves), shorter waves can reflect off the ionosphere and return to earth
beyond the horizon (skywaves), while much shorter wavelengths bend or diffract
very little and travel on a line of sight, so their propagation distances are limited to
the visual horizon.
Radio transmitters
A radio transmitter consists of several elements that work together to generate
radio waves that contain useful information such as audio, video, or digital data.

Power supply: Provides the necessary electrical power to operate the
transmitter.

Oscillator: Creates alternating current at the frequency on which the
transmitter will transmit. The oscillator usually generates a sine wave, which
is referred to as a carrier wave.

Modulator: Adds useful information to the carrier wave. There are two main
ways to add this information. The first, called amplitude modulation or AM,
makes slight increases or decreases to the intensity of the carrier wave. The
second, called frequency modulation or FM, makes slight increases or
decreases the frequency of the carrier wave.
Q2_STE_Electronics_ Module 2-3
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
Amplifier: Amplifies the modulated carrier wave to increase its power. The
more powerful the amplifier, the more powerful the broadcast.

Antenna: Converts the amplified signal to radio waves.
Radio receivers
A radio receiver is the opposite of a radio transmitter. It uses an antenna to capture
radio waves, processes those waves to extract only those waves that are vibrating at
the desired frequency, extracts the audio signals that were added to those waves,
amplifies the audio signals, and finally plays them on a speaker.

Antenna: Captures the radio waves. Typically, the antenna is simply a
length of wire. When this wire is exposed to radio waves, the waves induce a
very small alternating current in the antenna.

RF amplifier: A sensitive amplifier that amplifies the very weak radio
frequency (RF) signal from the antenna so that the signal can be processed
by the tuner.

Tuner: A circuit that can extract signals of a particular frequency from a mix
of signals of different frequencies. On its own, the antenna captures radio
waves of all frequencies and sends them to the RF amplifier, which dutifully
amplifies them all.
Unless you want to listen to every radio channel at the same time, you need
a circuit that can pick out just the signals for the channel you want to hear.
That’s the role of the tuner.
The tuner usually employs the combination of an inductor (for example, a
coil) and a capacitor to form a circuit that resonates at a particular
frequency. This frequency, called the resonant frequency, is determined by
the values chosen for the coil and the capacitor. This type of circuit tends to
block any AC signals at a frequency above or below the resonant frequency.
You can adjust the resonant frequency by varying the amount of inductance
in the coil or the capacitance of the capacitor. In simple radio receiver
circuits, the tuning is adjusted by varying the number of turns of wire in the
Q2_STE_Electronics_ Module 2-3
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coil. More sophisticated tuners use a variable capacitor (also called a tuning
capacitor) to vary the frequency.

Detector: Responsible for separating the audio information from the carrier
wave. For AM signals, this can be done with a diode that just rectifies the
alternating current signal. What’s left after the diode has its way with the
alternating current signal is a direct current signal that can be fed to an
audio amplifier circuit. For FM signals, the detector circuit is a little more
complicated.

Audio amplifier: This component’s job is to amplify the weak signal that
comes from the detector so that it can be heard. This can be done using a
simple transistor amplifier circuit.
There are many variations on this basic radio receiver design. Many receivers
include additional filtering and tuning circuits to better lock on to the intended
frequency — or to produce better-quality audio output — and exclude other
signals. Still, these basic elements are found in most receiver circuits
Engage
Answer what is asked.
1. Where are the radio waves located on the spectrum?
___________________________________________________________________________
___________________________________________________________________________
2. How many waves are there in the electromagnetic spectrum?
___________________________________________________________________________
___________________________________________________________________________
Apply
Give what is asked.
1. Enumerate the parts of the radio transmitter.
2. What are the two components required for radio communication?
3. Illustrate the parts of radio receiver in a block diagram format.
Q2_STE_Electronics_ Module 2-3
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Assess
Multiple Choice. Choose the letter of the best answer. Write the chosen letter on a
separate sheet of paper.
1. What refers to waves of energy that are found on the electronic spectrum?
a. Electromagnetic spectrum
b. radio receiver
c. radio wave
d. radio transmitter
2. Who proves the existence of radio waves?
a. Henry Heart
b. Heinrich Hertz
c. James Clerk Maxwell
d. Heinrich Herts
3. All electromagnetic waves travel through a vacuum at
a. At the same speed
b. Speed that are proportional to their frequency
c. Speed that are inversely proportional to their frequency
d. None of the above.
4. Which of the following has the longest wavelength?
a. Radio
b. Infrared
c. X-ray
d. Gamma rays
5. Which type of electromagnetic radiation is emitted by radio stations, stars,
and gases in space?
a. Microwave
b. Visible light
c. Radio wave
d. infrared
6. Which of the following converts the amplified signal to radio waves?
a. Oscillator
b. Amplifier
c. Antenna
d. Modulator
7. What is the job of the audio amplifier?
a. To separates the audio information from the carrier wave.
b. To amplifies the modulated carrier wave to increase its power.
c. To operates the waves.
d. To amplify the weak signal that comes from the detector so that it can
be heard.
8. Which of the following is responsible for separating the audio information
from the carrier wave?
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a. Detector
b. Tuner
c. Audio amplifier
d. oscillator
9. What are the two components which are require in radio communication?
a. Radio wave and spectrum
b. Radio receivers and transmitters
c. Infrared and gamma rays
d. Radio wave and antenna
10. How are radio waves received?
a. A radio wave is generated by a transmitter and then detected by a
receiver, an antenna allows a radio transmitter to send energy and a
receiver pick up energy from the space.
b. The radio wave send energy and the antenna receive the energy from
the space.
c. The transmitter detects the energy and sent it to the antenna.
d. The energy from the space detects by radio transmitter and received
by the radio receiver.
Reflect
Are radio waves harmful or helpful?
How are radio waves used in our daily life?
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Page 8 of 16
Engage
1.
2.
It is located at the
top
7
Apply
1.
2.
Power supply,
oscillator,
modulator, amplifier
and antenna
Radio transmitter
And radio receiver
3.
Q2_STE_Electronics_ Module 2-3
Assess
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
C
B
A
D
C
C
D
A
B
A
Answer Key
References
https://en.wikipedia.org/wiki/Radio_wave
https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html
https://www.dummies.com/programming/electronics/components/radioelectronics-transmitters-and-receivers
Q2_STE_Electronics_ Module 2-3
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Email Address: *region8@deped.gov.ph
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