10

Electronics
Quarter 4 - Module 1:
Types Of Power Supply
Circuit
Electronics 10
Special Science Class
Alternative Delivery Mode
Quarter 4 – Module 1: Types of Power Supply Circuit

First Edition, 2021

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 10

Electronics
Quarter 4 - Module 1:
Types Of Power Supply
Circuit

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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 each lesson.

Each SLM is composed of different parts. Each part shall guide you step-by-step as
you discover and understand the lesson prepared for you.

Pre-tests are provided to measure your prior knowledge on lessons in each SLM. This
will tell you if you need to proceed on completing this module or if you need to ask your
facilitator or your teacher’s assistance for better understanding of the lesson. At the
end of each module, you need to answer the post-test to self-check your learning.
Answer keys are provided for each activity and test. We trust that you will be honest in
using these.

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 part of this
SLM. Use a separate sheet of paper in answering the exercises and tests. And read
the instructions carefully before performing each task.

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.

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 What I Need to Know

This module was designed and written with you in mind. It is here to help you master
the theories and applications of TYPES OF POWER SUPPLY CIRCUIT! The scope of
this module permits it to be used in many different learning situations. The language
used recognizes the diverse vocabulary level of students. The lessons are arranged to
follow the standard sequence of the course. But the order in which you read them can
be changed to correspond with the textbook you are now using.

After going through this module, you are expected to:

demonstrate the functional understanding on the importance of power supply
circuit and its types. Specifically, the learners are going to:

1.1 identify the different types of power supply circuit; and

1.2 describe the operations of the different types of power supply.

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 What I Know

Directions: Read each item comprehensively. Choose the letter of the correct answer.
Use a separate sheet of paper.
1. Which of the following can be defined as an electrical device that is
used to give electrical supply to electrical loads?
A. Power
B. Power Source
C. Power Supply
D. Circuit

2. Sometimes, these power supplies can be named to as electric power

__________.
A. converters
B. inverters
C. suppliers
D. source

3. Which type is also called as computer power supply?

A. Switched Mode Power Supply
B. Uninterruptible Power Supply
C. AC Power Supply
D. DC Power Supply

4. This type of power supply has advantages which include reliability, simplicity,
low cost, and its noise level is low.
A. Regulated Linear Power Supply
B. Programmable Power Supply
C. Computer Power Supply
D. Unregulated Linear Power Supply

5. The main function of this circuit is at first; step down the alternating current
voltage then changes it into direct current.
A. Unregulated Linear Power Supply
B. DC Power Supply
C. AC Power Supply
D. Uninterruptible Power Supply

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 What’s In

Directions: Circle the words that can be found from the 12 listed words below. They
appear straight across, backword straight across, up and down, down
and up, and diagonally.

WORDS:
POWER SUPPLY CIRCUIT DIAGRAM
TRANSFORMER RECTIFIER FILTER
REGULATOR INVERTER TRANSISTOR
CAPACITOR VARIABLE UNINTERRUPTIBLE

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 What’s New

The power supply unit is the part of the hardware that is used to convert the power
provided from the outlet into usable power to many parts inside an electrical device.
Every energy supply must drive its load, which is connected to it. Depending on its
design, a power supply unit may obtain energy from various types of energy sources,
like electrical energy transmission systems, electromechanical systems such as
generators and alternators, solar power converters, energy storage devices such as
a battery and fuel cells, or other power supply. There are two types of power supplies
existed, AC and DC power supply. Based on the electrical device’s electric
specifications it may use AC power or DC power.

What is It

Lesson TYPES OF POWER SUPPLY

1 CIRCUIT
The power supply is the essential component in every electrical or electronic system.
There are various requirements that need to be considered while choosing an exact
power supply such as; necessities of power for the circuit or load mainly include voltage
and current. The safety features of the power supply circuit like current and voltage
limits for protecting the load, efficiency, physical size, and system noise immunity. In
this module, we look into the definition of a power supply, different types of power
supplies, and how they work.

WHAT IS A POWER SUPPLY?

The power supply can be defined as it is an electrical device used to give electrical
supply to electrical loads. The main function of this device is to change the electrical
current from a source to the accurate voltage, frequency and current to supply the
load. Sometimes, these power supplies can be named to as electric power converters.
Some types of supplies are separate pieces of loads, whereas others are fabricated
into the appliances that they control.

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POWER SUPPLY BLOCK DIAGRAM
The Power supply circuit is used in various electrical & electronic devices. The power
supply circuits are classified into different types based on the power they utilize for
providing for circuits or devices. For instance, the microcontroller-based circuits are
generally the 5V DC regulated power supply (RPS) circuits, which can be designed
with the help of different method for changing the power from 230V AC to 5V DC.

The power supply block diagram, and the step-by-step conversion of 230V AC to 12V
DC is discussed below.
• A step-down transformer converts the 230V AC into12v.
• The bridge rectifier is used to change AC to DC
• A capacitor is used to filter the AC ripples and gives to the voltage regulator.
• Finally, voltage regulator regulates the voltage to 5V and finally, a blocking
diode is used for taking the pulsating waveform.

Filter

Power Supply Block Diagram

CLASSIFICATION OF POWER SUPPLY AND ITS DIFFERENT TYPES

Here we will discuss different types of power supplies which have existed in the market
world. The below table tells the basic types of power supplies for following conditions.
OUTPUT = DC OUTPUT = AC
• Wall wart • Isolation transformer
INPUT = AC • Bench power supplies • Variable AC supply
• Battery charger • Frequency changer
• Inverter
INPUT = DC • DC-DC converter • Generator
• UPS

SMPS- Switched Mode Power Supply

An SMPS power supply or computer power supply is one type of power supply that
includes a switching regulator for converting electrical power powerfully. Similar to
other power supplies, this power supply transmits the power from a DC source or AC
source to DC loads, such as a PC (personal computer), while changing the
characteristics of current and voltage.

SMPS – Switched Mode Power Supply

https://bit.ly/3hIWZ6N

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The SMPS has a rectifier, filter capacitor, series transistor, regulator, transformer, but
is more complicated than the other power supplies that we have discussed.

The above-shown schematic is a simple block diagram. The AC voltage is rectified to

an unregulated DC voltage, with the series transistor and the regulator. This DC is
chopped to a constant high-frequency voltage which enables the size of the
transformer to be dramatically reduced and allows for a much smaller power supply.
The disadvantages of this type of supply are that all of the transformers have to be
custom-made and the complexity of the power supply does not lend itself to low
production or economical low power applications.

1. Uninterruptible Power Supply

The full form of the UPS is an uninterruptible power source or uninterruptible power
supply. It is an electrical device that gives
emergency power to various loads when the input
power typically fails. A UPS fluctuates from an
emergency power system in that it will deliver
near-instantaneous safety from i/p power
interruptions by providing energy stored in
batteries, super capacitors. The run time of
battery for most UPS is relatively short but
enough to start a standby power source. The
main purpose of a UPS is to provide a protection
to the equipments like computers, electrical
equipment, computer and data centers when
there is a power disruption. This device keeps a
https://bit.ly/349SkCM computer running for a few minutes after a power
disruption and protects the data in the computer. In present days, there are various
types of UPS systems coming with software component that enables you to automobile
backup in case there is no power disruption when you are away from the computer.

A UPS (uninterruptible power supply) is an electrical device that permits a PC to keep

working for some time as the main power supply is lost. This device is also give
protection from power flow. A UPS includes a battery to store the energy when the
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device detects a power loss from the main source. For instance, if you are using the
PC when the uninterruptible power supply senses the power loss, then you have to
save the data before the UPS (secondary power source) discharges. When both the
primary and secondary power sources run out, any data in your PC’s RAM (random
access memory) is erased. When power loss occurs, a secondary power source stops
the loss of power so that it does not harm the personal computer.

Uninterruptible Power Supply Circuit Diagram

The circuit diagram of the UPS is shown below, which shows how the batteries in the
equipments controls during a power disruption. The input voltage of the primary
winding of the transformer (TR1) is 240V. The secondary winding of the transformer
(TR2) can be raised up to 15V if the value is at least 12V running 2 amps.The fuse is

used to give the protection to the owl circuit from the short circuits. The electricity
presence will cause the led1 to glow. The LED glows will set off upon power disruption
and the battery of the UPS will take over. This circuit is designed to provide a more
flexible pattern where it can be modified by using different batteries and regulators to
offer regulated & unregulated voltages. Using two 12V batteries in series and a positive
input of 7815 regulators, we can control a 15Volts supply.

2. Variable AC Power Supply

The different AC voltages are generated by using a transformer. The transformer may
have multiple windings or taps, in which case the instrument uses switches to select
the different voltage levels. Alternatively, a variable transformer (adjustable
autotransformer) can be used to continuously vary the voltages. Some variable AC
supplies are included meters to monitor the
voltage, current, and/or power.
Typically, an AC power supply acquires the
voltage from the mains supply and the
voltage can be step up or step down by using
a transformer to the required voltage and
some filtering may take place. The different
types of AC power supplies are designed to
offer an almost stable current, and o/p voltage
may change based on the load’s impedance.
In some cases, as the power supply is DC, a
step-up transformer and an inverter may be
https://bit.ly/3bNcaI9
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utilized for converting it into AC power. Some sorts of AC power alteration do not use
a transformer.
If the input and output voltages are the similar and main function of the apparatus is to
filter AC power. If the apparatus is designed for providing backup power, then it may
be named as an uninterruptable power supply (UPS). At present, AC power supplies
are classified into two types: the single - phase systems and the three - phase systems.
The main differences between these two are dependability of delivery. These supplies
can also be applicable for changing the voltage as well as frequency.

3. DC Power Supply
A DC power supply is one that provides a consistent DC voltage to its load. Based on
its plan, a DC power supply
might be controlled from a DC
supply or from an AC supply
like the power mains.

4. Regulated Linear Power

Supply
Regulated linear power
supplies are same as the
unregulated linear power
supply except that a 3-
terminal regulator is used in place of the bleeder resistor. The main aim of this power
supply is to provide the required level of DC power to the load. The DC power supply
uses an AC supply as the input. Different applications require different levels of
attributes voltages, but nowadays the DC power supplies provide an accurate output
voltage. And this voltage is regulated by an electronic circuitry so that it provides a
constant output voltage over a wide range of output loads.

Here is the basic circuit diagram for Regulated Linear Power Supply given below.

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The main features of this power supply include the following.
• The efficiency of this power supply ranges from 20 to 25%
• The magnetic materials used in this power supply are CRGO core or Stalloy.
• It is more reliable, less complex and bulky.
• It gives a faster response.

The main advantages of regulated linear power supply include reliability, simplicity, low
cost and the noise level is low.

These are best for several low power applications as a result when a high-power is
required, the drawbacks turn into more clearly. The disadvantages of this power supply
include a high loss of heat, size, & low-efficiency level. Whenever linear power supply
is used in high power applications, it requires large components to manage the power.

Smoothing
Once rectified from an AC signal, the DC needs to be smoothed to remove the varying
voltage level. Large value capacitors are generally used for this purpose.

Voltage Regulator
A linear regulator has an active (BJT or MOSFET) pass device (series or shunt)
controlled by a high gain differential amplifier. It compares the output voltage with a
precise reference voltage and adjusts the pass device to maintain a constant level
output voltage.

Series regulator
This is the most widely used regulators for linear power supplies. As the name implies
a series element is placed in the circuit as shown in below figure, and its resistance
varied via the control electronics to ensure that the correct output voltage is generated
for the current taken.

Concept of the Series Voltage Regulator or Series Pass Regulator

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Shunt regulator
The shunt regulator is less widely used as the main element within a voltage regulator.
In this, a variable element is placed across the load as shown in below. There is a
source resistor placed in series with the input, and the shunt regulator is varied to make
sure that the voltage across the load remains constant.

5. Programmable Power Supply

This type of power supply permits remote control for its operation via analog input
otherwise digital interfaces like GPIB or RS232. The controlled properties of this supply
include current, voltage, frequency. These types of supplies are used in a wide range
of applications like fabrication of semiconductors, X-ray generators, monitoring of
crystal growth, automated apparatus testing.
Generally, these types of power supplies use an essential microcomputer for
controlling as well as monitoring the operation of a power supply. A power supply
provided with an interface of computer uses standard (or) proprietary communication
protocols, and device control language like SCPI (standard-commands-for-
programmable-instruments)

6. Computer Power Supply

The power supply unit in a computer is the part of the hardware that is used for
changing the power supplied from the outlet into utilizable power for the several parts
of the computer. It converts the alternating current into direct current.
It also controls over-heating through controlling voltage, which may modify manually
or automatically based on the power supply. The PSU or power supply unit is also
called as a power converter or a power pack.
In a computer, the internal components like cases, motherboards, & power supplies all
available in different configurations, sizes which are known as form factor. All these
three components must be well-matched to work appropriately together.

7. Unregulated Linear Power Supply

The ULPS (unregulated linear power supply) circuit is used in various electrical &
electronic circuits for supplying the DC current to the entire circuit. The unregulated
linear power supply mainly includes a step-down transformer, rectifier, filter capacitor
& a bleeder resistor. The main function of this circuit is at first; step downs the
alternating current voltage then changes it into direct current.

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This type of power supply, because of simplicity, is the least costly and most reliable
for low power requirements. The main disadvantage is that the output voltage is not
constant. It will vary with the input voltage and the load current, and the ripple is not
suitable for electronic applications. The ripple can be reduced by changing the filter
capacitor to an LC (inductor-capacitor) filter, but the cost becomes more.

Input transformer
The input transformer is used to convert the incoming line voltage down to the required
level of the power supply. It also isolates the output circuit from the line supply. Here
we are using a step-down transformer.

Rectifier
The rectifier used to convert the incoming signal from an AC format into raw DC. Please
refer these links, Different types of rectifiers available are half wave rectifier and full-
wave rectifier.
Filter Capacitor
The pulsated DC from the rectifier is fed to the smoothing capacitor. It will remove the
unwanted ripples in the pulsated DC.

Bleeder Resistor
Bleeder Resistor is also known as a power supply drain resistor. It is connected across
the filter capacitors to drain their stored charge so that the power system supply is not
dangerous.

Thus, this is all about different types of power supplies, and these are being used for
providing the power supply to different systems efficiently. Power supplies are the
essential components of every system to get electrical energy for the operation. So,
some of the considerations of a power supply like design or development are more
significant. Because day-by-day the invention of technology as well as power supplies
are being increased for providing protection to electrical and electronic devices.

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 What’s More

Directions: Identify the following whether they are SMPS, UPS, VACPS, DCPS,
RLPS, PPS, CPS, or ULPS.
Because of simplicity, this type of power supply is the least costly
1
and most reliable for low power requirements.
It also controls over-heating through controlling voltage, which
2
may modify manually or automatically based on the power supply.
This type of power supply permits remote control for its operation
3
via analog input otherwise digital interfaces like GPIB or RS232.
The main aim of this power supply is to provide the required level
4 of DC power to the load. The DC power supply uses an AC supply
as the input.
It is a power supply that provides a consistent DC voltage to its
5
load.
Typically, this power supply acquires the voltage from the main
6 supply and the voltage can be stepped up or stepped down with
the use of transformer.
One type of power supply includes a switching regulator for
7
converting electrical power powerfully.
The main purpose of this power supply is to provide a protection
8 to the equipment like computers, electrical equipment, computer
and data centers during a power disruption.

What I Have Learned

Describe each type of power supply.

1. Switched Mode Power Supply
2. Uninterruptible Power Supply
3. Variable AC Power Supply
4. DC Power Supply
5. Regulated Linear Power Supply
6. Unregulated Linear Power Supply
7. Computer Power Supply
8. Programmable Power Supply

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 What I Can Do

Directions:
✓ Draw a schematic diagram of at least two types of power supply of your
choice.

Assessment

Directions: Choose the letter of the correct answer. Write your answers on a separate
sheet of paper.
1. Which type of power supply has a switching regulator for converting electrical
energy powerfully.
A. Variable AC Power Supply C. Uninterruptible Power Supply
B. Switched Mode Power Supply D. DC Power Supply

2. Which of the following is a correct statement for Uninterruptible Power Supply?

A. Voltages are generated by using a transformer.
B. It is an electrical device that gives emergency power to various loads
when the input power typically fails.
C. It permits remote control for its operation via analog input otherwise
digital interfaces like GPIB or RS232.
D. Because of simplicity, this type of power supply is the least costly and
most reliable for low power requirements.

3. How would you describe a rectifier?

A. It is used to convert the incoming line voltage down to the required level
of the power supply.
B. It is used to convert the incoming signal from an AC format into raw DC.
C. It will remove the unwanted ripples in the pulsated DC.
D. It is a power supply drain resistor.

4. The main advantages of this power supply are reliability, simplicity, low cost and
its noise level is low.
A. Regulated Linear Power Supply
B. Unregulated Linear Power Supply
C. Programmable Power Supply
D. Computer Power Supply

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5. What is the function of block B?

A B C D

A. Transformer C. Rectifier
B. Filter D. Regulator

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 Answer Key

What I Know What I Have Learned

1. C Answers may vary.
2. A
3. A
4. A
5. A Assessment

1. B
2. B
3. B
4. A
5. C

References

® https://www.allaboutcircuits.com/textbook/semiconductors/chpt-
9/power-supply-circuits/
® https://www.watelectrical.com/what-is-a-power-supply-and-types-
of-power-supply-for-electrical-circuits/
® https://learnabout-electronics.org/PSU/psu13.php
® https://www.elprocus.com/classification-power-supply-different-
types/

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For inquiries or feedback, please write or call:

Department of Education – Carcar City Division (Learning Resources

Management Section)

P. Nellas St., Población III, Carcar City, Cebu Philippines 6019

Tel. No. 4878495

Email Address: carcarcitydivision@yahoo.com

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