Republic of the Philippines
Department of Education
PUBLIC TECHNICAL -VOCATIONAL
HIGH SCHOOLS
Unit of Competency:
Module No:
1
ASSEMBLE AND DISASSEMBLE CONSUMER
ELECTRONIC PRODUCTS AND SYSTEM
Module Title:
ASSEMBLING AC-DC POWER SUPPLY
TABLE OF CONTENTS
Page
How to Use this Module ..................................................................................... i
Introduction ..................................................................................................... ii
Technical Terms .............................................................................................. iii
Learning Outcome 1: Identify he parts and electronic components
of AC-DC power supply…………… .................................... 1
 Information Sheet 1.1 ............................................................................. 3
 Self-Check 1.1 ....................................................................................... 11
 Self-Check Key 1.1 ................................................................................ 12
 Self-Check 1.2 ....................................................................................... 13
 Self-Check Key 1.2 ............................................................................... .14
Learning Outcome 2: Assembling AC-DC power supply…………...………………..16
 Information Sheet 2.1…...……………………………………………………........18
 Self-Check 2.1………………………………………………………………………...20
 Self-Check Key 2.1…………………………………………………………..….……21
 Operation Sheet 2.1………………………………………………….………………22
 Performance Check 2.1………………………………..……………………………25
 Information sheet 2.2………………………………………………………..….…..26
 Job Sheet 2.1………………………………………………………….……….….…..27
 Assessment Checklist 2.1…………………………………………..……………...31
 Operation Sheet 2.3………………………………………………………………….33
 Scoring Rubrics for Operation Sheet 2.3…………………………....…….…...36
 Job Sheet 2.2…………………………………………………………………….……37
 Assessment Checklist for Job Sheet 2.2…………………………..……………40
Assessment Plan……………………………………………………………………….……..41
 Observation Checklist……………………………………………………….………42
 Observation and Questioning Checklist……………………………….………..43
 Demonstration Checklist…………………………………………………….……..44
 Written Report………………………………………………………………….……..45
 Performance Test…………………………………………………………….……….46
References …………………………………………………………………………………….47
Acknowledgment …………………………………………………………………………….48
HOW TO USE THIS MODULE
Welcome to the Module “Assembling AC-DC Power Supply”. This module
contains training materials and activities for you to complete.
The unit of competency “Assemble and Disassemble Consumer Electronic
Products and Systems” contains the knowledge, skills and desirable attitudes
required for Consumer Electronic Servicing to obtain the National Certificate
(NC) level II.
You are required to go through a series of learning activities in order to
complete each of the learning outcomes of the module. In each learning outcome,
there are Information Sheets, Job Sheets and Operation Sheets. Do these
activities on your own and answer the Self-Check at the end of each learning
activity.
If you have any question, don’t hesitate to ask your teacher for an assistance.
Recognition of Prior Learning (RPL)
You have already some basic knowledge and skills covered in this module
because you have been working for some time; or have already completed training
in this area.
If you can demonstrate competence to your teacher in a particular skill, talk
to your teacher so you don’t have to undergo the same training again. If you have
a qualification or Certificate of Competency from previous trainings show it to
him/her. If the skills you acquired are relevant to this module, they become part
of the evidence. You can present these for RPL. If you are not sure about your
competence skills, discuss this with your teacher.
After completing this module, ask your teacher to assess your competence.
Result of your assessment will be recorded in your competency profile. All the
learning activities are designed for you to complete at your own pace.
In this module, you will find the activities for you to complete and relevant
information sheets for each learning outcome. Each learning outcome may have
more than one learning activity.
This module is prepared to help you achieve the required competency, in
receiving and relaying information. This will be the source of information that
will enable you to acquire the knowledge and skills in Assembling and
Disassembling Consumer Electronic Products and Systems and
independently at your own pace with minimum supervision from your teacher.
i
Program/Course:
CONSUMER ELECTRONIC SERVICING NC II
Unit of Competency:
ASSEMBLE AND DISASSEMBLE CONSUMER
ELECTRONIC PRODUCTS AND SYSTEMS
Module Title:
ASSEMBLING AC-DC POWER SUPPLY
INTRODUCTION:
This module contains information and suggested learning activities on
Assembling AC-DC Power Supply. It covers the knowledge, skills and desirable
attitudes required in assembling consumer electronic products and systems.
This module consists of two (2) learning outcomes. Each learning outcome
contains learning activities supported by instructional sheets. Before you
perform the instructions, read the information sheets and answer the self-check
and activities provided to ascertain to yourself and your teacher that you have
acquired the knowledge necessary to perform the skill portion of the particular
learning outcome.
Upon completing this module, report to your teacher for an assessment to
check your achievement of knowledge and skills required in this module. If you
pass the assessment, you will be given a certificate of completion.
SUMMARY OF LEARNING OUTCOMES:
Upon completion of the module, you should be able to:
LO1. identify the parts and electronic components of AC-DC power supply;
and
LO2. assemble AC-DC power supply to the printed circuit board.
ASSESSMENT CRITERIA:
Refer to the assessment criteria of learning outcomes 1-2 of this module.
PREREQUISITE:




Using hand tools
Performing mensuration and calculation
Preparing and interpreting Technical Drawing used in Electronics
Applying Quality Standards
ii
TECHNICAL TERMS
AC/DC. An equipment that operates on either an AC or DC power source.
Anode. The positive electrode of a device. The “P” material of a diode.
Bridge Rectifier. A circuit using four diodes that provides full wave rectification. Converts AC voltage to pulsating DC voltage.
Calibration. To adjust the correct value of a reading by comparison with the
Standard.
Color Code. Set of colors used to indicate value of a component.
Full Wave Rectifier. The rectifier that makes use of full AC wave in both
Both positive and negative half cycles.
Half Wave Rectifier. A diode rectifier that converts AC to pulsating DC by
eliminating either the negative or positive alternation of
each input AC cycle.
Leakage. A small undesirable flow of current through an insulator.
Output. A terminal at which a component, circuit or piece of equipment
delivers current, voltage, or power.
Primary winding. The first winding of a transformer. Winding that is
connected to the source as opposed to secondary which is
a winding connected to the load.
Printed Circuit Board. An insulating board containing conductive parts for
Circuit connections.
Regulated Power Supply. A power supply where the output voltage is not
affected by its loading factor.
Schematic Diagram. An illustration of an electrical or electronic circuit with
the components represented by symbols.
Secondary Winding. An output winding of a transformer that is connected
to the load.
Short Circuit. A very low resistance between two points in a circuit causing
excessive current.
iii
Program/Course:
CONSUMER ELECTRONIC SERVICING NC II
Unit of Competency:
ASSEMBLE AND DISASSEMBLE CONSUMER
ELECTRONIC PRODUCTS AND SYSTEM
Module Title:
ASSEMBLING AC-DC POWER SUPPLY
Learning Outcome 1: Identify the parts and the electronic components of an
AC-DC power supply.
Assessment Criteria
1. The types of AC-DC power supply are enumerated.
2. The parts of an AC-DC power supply are identified.
3. The electronic components needed in assembling AC-DC power supply
are listed and acquired.
1
LEARNING EXPERIENCES/ACTIVITIES
Learning Outcome 1: Identify the parts and electronic components of an
AC-DC power supply.
Learning Activities
1. Read the attached Information
Sheet 1.1 on AC-DC Power
supply.
a. Types of AC-DC Power
Supply
b. Parts of AC-DC Power
Supply
Special Instruction

Try to answer the Self-Check 1.1
without looking at the
information sheet.
c. Electronic Components
and Symbols used in ACDC Power Supply
2
INFORMATION SHEET 1.1
AC-DC Power Supply
A power supply is the heart
of all electronics equipment. It
converts AC input power line to DC
output voltage. It is the one that
supplies the desired voltage or
current in a circuit. Without it, all
of the electronic equipment will
not function properly or will be a
dead set.
AC-DC Power Supply
TYPES OF AC-DC POWER SUPPLY
A basic power supply consists of three basic stages: the power transformer
stage, rectifier stage, and filter stage. An additional stage is sometimes added if
there is a need for regulation. This stage is called regulator.
AC
Outp
ut
Transformer
Stage
Rectifier
Stage
Filter
Stage
Block Diagram of AC-DC Power Supply
DC
Outp
ut
3
1. Half-Wave Rectifier Circuit
One rectifier diode D1 and one load resistor RL are needed to conduct
one alteration in every cycle of small AC input.
Schematic Diagram of A Half-Wave Rectifier
2. Full-Wave Center-Tapped Rectifier Circuit
Using this type of circuit, you’ll need a center-tapped transformer,
two rectifier diodes and a load resistor (RL). Each of the diode supplies onehalf the DC load current.
4
Schematic Diagram of A Full-Wave Center Tapped Rectifier circuit
3. Full-Wave Bridge Type Rectifier Circuit
Schematic Diagram of A Full-Wave Power Supply
The previous circuit illustration uses four rectifier diodes D1 D2 D3 D4 and
a load resistor (RL). Bridge circuit makes it possible to remove the center-tapped
transformer. Among the types of power supply this circuit can deliver a higher
current range to the load because all of cycles are consumed by the four diodes.
The operation of this rectifier circuit is different from the half-wave and fullwave center tapped. The conduction of AC voltage starts from Line-A going to
the Line-B.
First Conduction
The negative half-cycle will be going to conduct to the cathode of diode D1,
thru the RL and going to conduct to the cathode of diode D4 then Line-B. In this
case D1 and D4 are conducting.
5
First Conduction in a Full Wave Power Supply
Second Conduction
The positive half-cycle will be going to conduct to the anode of diode D2,
thru the RL and going to conduct to the anode of diode D3 then Line-B. In this
case D2 and D3 are conducting.
Second Conduction in a Full Wave Power Supply
Characteristics of a Full Bridge Type Power Supply
a. Expensive
b. Needs a lower value of capacitance
c. Needs four rectifier diodes
Filter Stage
The filtering stage is one of the stages of the power supply which filters the
pulsating DC. Output of rectifier stage and make it a pure DC voltages. The main
function of the filter circuit is to increase the DC output and to smoothen the
pulsating DC.
Insufficient filtering
This can cause distortion.
Rectifier
Stage
Filter
Stage
(+)
6
Filter Stage
Basic Methods of Filtering
1. Simple Capacitor in Parallel
You can parallel as many electrolytic capacitors as you want. This will
increase the amount of capacitance causing good filtering effects to DC
output. This is used for high current applications. The only disadvantage is
that it will occupy a bigger space.
Placing additional
capacitor in the
output.
Filter Circuit
2. Filter with RC Circuit
This circuit is actually a resistor in series with the positive line together with 2
bypass capacitor C1 & C2. It is good in lowering the DC voltage output.
Placing a resistor in series
with the positive line can
cause voltage drop.
7
Filter with RC Circuit
3. Filter with Inductor
This circuit has a good filtering effect to the pulsating DC output of the
rectifier. It uses minimal value of capacitance and it is good in low current
and high current application. The only disadvantage is that the inductor
in series with the positive line takes up big space in mounting it in the PC.
Filter with Inductor
External Parts of AC-DC Power Supply
8
The external parts of an AC-DC power
supply are as follows:

Front Pane. It contains the power
switch, voltage selector switch, and
the power indicator.
Front Panel

Rear Panel. It contains the fuse and
the AC line cord.
Rear Panel
Internal Parts of AC-DC Power Supply
The internal parts of the AC-DC Power Supply are shown in the figure below.
Internal Parts of an AC-DC Power Supply
9
Parts of AC-DC Power Supply
Component Description
s
Alligator
Clip
A special type of connector used to connect the power supply
to the electronic gadget.
Capacitor
A capacitor acts as the filter. The one that removes ripples
from the output of the rectifier circuit. The type of capacitor
used in this purpose is the electrolytic capacitor.
Case and
Cover
It serves as the housing of an AC-DC power supply.
Diode
A device which only allows current to flow in only one
direction.
Fuse
A protective device used to prevent the circuit from short
circuit
or damage
LED
Light Emitti
ng Diode
A transducer which converts electrical energy to light.
Line cord
A type of cord used to connect the unit to the voltage source.
On-Off
switch
Used to switch on and off the circuit.
Printed
Circuit
Board
PCB – a conductive pattern formed on one or both sides of an
insulating base by etching, plating or stamping.
10
Resistor
A resistor restricts the flow of current (eg. to limit the current
passing through an LED). A resistor is used with a capacitor
in a timing circuit.
Some publications still use the old resistor symbol.
Rotary
Switch
A switch that is operated by a rotating shaft.
Transforme A component that consist of two or more coils which are
r
coupled together by magnetic induction.
11