Electronics-Y3.pdf

Unit of Competency: ASSEMBLE AND DISASSEMBLE CONSUMER ELECTRONIC PRODUCTS AND SYSTEM

Module No: 1 Module Title: ASSEMBLING AC-DC POWER SUPPLY Republic of the Philippines

Department of Education PUBLIC TECHNICAL -VOCATIONAL

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

i

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.

ii 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

iii

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 rectifi- cation. 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.

1 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.

2

LEARNING EXPERIENCES/ACTIVITIES

Learning Outcome 1: Identify the parts and electronic components of an AC-DC power supply.

Learning Activities Special Instruction 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

c. Electronic Components and Symbols used in AC-DC Power Supply

 Try to answer the Self-Check 1.1 without looking at the

3

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.

Block Diagram of AC-DC Power Supply

AC

Outp

ut

DC

Outp

ut

Transformer Stage Rectifier Stage Filter Stage

4 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 one-half the DC load current.

5 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 full-wave 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.

6 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. Filter Stage

(

+

)

(-)

Rectifier Stage Filter Stage

Insufficient filtering

This can cause distortion.

7 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.

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.

Filter with RC Circuit

Placing additional capacitor in the output.

Placing a resistor in series with the positive line can cause voltage drop.

8 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 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.

9 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

Parts of AC-DC Power Supply Components Description 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

10 LED

Light Emittin g 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.

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.

Transformer A component that consist of two or more coils which are coupled together by magnetic induction.

11

SELF-CHECK 1.1

AC-DC Power Supply

GENERAL DIRECTION: Write all your answers in separate sheets of paper. Do not write anything in this module.

Direction: Answer the following questions below.

1. How many stages do basic power supplies have?

2. What component do we need to use in a simple basic filtering stage? 3. Why is a bridge type rectifier the most expensive type rectifier stage?

4. What stage of the power supply step-down the high AC voltage to lower AC voltage?

5. What stage of the power supply converts small AC voltage to pulsating DC voltage?

6. How many basic methods of filtering do the filtering stages have? 7. How many types of rectifier circuits do basic power supplies have?

8. What stage of the power supply smoothens the pulsating DC into pure DC output voltages?

9. How many diodes full-wave center tapped power supplies have? 10. Why is a half-wave rectifier the cheapest type rectifier stage?

12

SELF-CHECK KEY 1.1

AC-DC Power Supply

1. Three

2. Filter Capacitor / Electrolytic Capacitor 3. It uses four rectifier diodes

4. Transformer stage 5. Rectifier stage 6. Three 7. Three 8. Filter Stage 9. Two

13

SELF-CHECK 1.2

Assembling AC-DC Power Supply

I. Direction: Fill in the blank with the names of the parts indicated in the diagram. (1-9). Write the answer in your test notebook.

__________10. Based on the given circuit, what type of power supply is this?

II. Direction: Draw the schematic diagram of the following circuit: a. Half-wave power supply b. Full-wave conventional c. Full-wave bridge type

_________2. __________1. _________9. _________8. ________6. ________7. ________5. _________3. _______4.

14

SELF-CHECK KEY 1.2

I. 1. Transformer 2. AC plug 3. LED

4. Rotary Switch knob 5. Alligator Clip

6. Rubber Grommet 7. Rotary Switch

8. Printed Circuit Board 9. Fuse Holder

10. Full-wave Bridge Type Power Supply II.

15 b. Full-wave conventional

c. Full-wave bridge type

Primary

Windings

16 Program/Course CONSUMER ELECTRONIC SERVICING NC II

Unit of Competency ASSEMBLE AND DISASEMBLE CONSUMER _{ELECTRONIC PRODUCTS AND SYSTEMS}

Module Title ASSEMBLING AC-DC POWER SUPPLY

Learning Outcome 2: Assemble AC-DC power supply to the printed circuit board.

Assessment Criteria

1. Printed Circuit Board design and etching for AC-DC power supply are prepared.

2. Electronic components are mounted and soldered at the appropriate location on the Printed Circuit Board.

3. All auxiliary components, including the transformer are interconnected to the Printed Circuit Board.

17

LEARNING EXPERIENCES/ACTIVITIES

Learning Outcome 2: Assemble AC-DC power supply to the Printed Circuit Board.

Learning Activities Special Instructions 1. Read the attached Information

Sheet 2.1 about the Preparation of PCB of an AC-DC Power Supply. 2. Answer the Self-Check 2.1. 3. Compare your answers with the

Self Check Key 2.1. 4. If you missed some of the

questions, go over the Information Sheet again.

5. Read the attached Operation Sheet 2.1 on mounting and soldering electronic components.

6. Read the Information Sheet 2.2 on:

a. Interconnecting all auxiliary components

b. Components including the transformer interconnecting all auxiliary Electronic

Components and Symbols of AC-DC Power Supply

7. Perform the Job Sheet 2.1. 8. Do the assessment check list 2.1 and 2.2.

9. Read the Information sheet 2.3. 10. Perform the Job sheet 2.2.

 Try to answer the Self-Check 2.1 without looking at the

information sheet.

 Mount and solder components in the PCB.

 Connect all the auxiliary

components of an AC-DC Power Supply.

 Power on the AC-DC power supply.

 Prepare and design the Printed Circuit Board.

 Mount and solder electronic components.

 Test voltage.

 Refer to the teacher’s

Assessment Check list 2.1 and 2.2.

 Refer to the teacher’s

Assessment Check list 2.3.  Refer to the teacher’s

18

INFORMATION SHEET 2.1

Designing and Etching PCB of AC-DC Power Supply

A printed circuit board (PCB) has components inserted into the hole and soldered to form its circuit connection. Its main purpose is to reduce the space and to troubleshoot easily when problem arises.

The printed circuit board (PCB) has conductors that are thin strip of copper, usually bonded to a baseboard called substrate. There are two very common substrate materials used in printed circuit, the phenolic and epoxy plastic.

Printed Circuit Board

Printed Circuit Board Etching is where the excess copper is removed to leave the individual tracks or traces as they are sometimes called. Buckets, bubble tanks, and spray machines are tools to do different ways of etching but most firms currently use high pressure conveyors spray equipment. Spray etching is fast Ammoniacal etching solutions when sprayed can etch 55 microns of copper a minute. Less than 40 seconds to etch a standard 1 oz, 35 micron circuit board.

Printed Circuit Board Etching

Many different chemical solutions can be used to etch circuit boards ranging from slow controlled speed etches used for surface preparation to the faster etches used for etching the tracks. Some are best used in horizontal spray process equipment while others are best used in tanks. Enchants for PTH work have to be selective and be non aggressive to tin / tin lead plating, which is used as the etch resists. Copper etching is normally exothermic where high

Substrate

Copper

19 speed etching is carried out solution cooling is normally required. This is normally done by placing titanium water cooling coils into the enchant. Almost all etching solutions liberate toxic corrosive fumes. Extraction is highly recommended. All enchants are corrosive and toxic mainly due to the high metal content. P.P.E. Personal Protection Equipment must always be used. Spent solutions should always be disposed properly and not to be spilled down local drains where they can pollute local sewage works and rivers.

Manufacturing of Printed Circuits in the Copper Clad Board

In PCB designing, we should not focus only on the size of the pathways linking to the other component, but also on the types, kinds, and characteristics of component. Here are the other design factors needed:

1. PCB size and shape. The PCB must be big enough for the entire component to be mounted where it is anticipated.

2. Position of the Terminal. Input, output and supply voltage if possible should be placed near the border for easier way during troubleshooting or minor repair.

3. High Temperature Dissipation. Too much heat is the number one problem of all components. Bigger space is needed so that heat sink can be provided to the component. This will protect the component from burning up.

4. Accessibility of Components. This component that is adjustable or variable (example: potentiometer, trimmer resistor or capacitor) should be placed near the border to make the troubleshooting or minor repair easier.

5. Space for Bolt and Nut. The designer should place an allowance for mounting the PCB with bolt and nut in securing the entire board to the chassis.

6. Different Types of Circuit Should be Grouped according to its

Application. This will enhance the circuit operation and will prevent it

from distortion generated by other circuit. This is the reason why the circuit of the power supply is far from the audio circuit.

20

SELF-CHECK 2.1

Designing and Preparing PCB of AC-DC Power Supply

Direction: Identify the following items.

1. A board that is open with electronic components is mounted and soldered.

2. A conductor where the component’s terminal lead is soldered.

3. It consists of a thin copper layer which is firmly bonded to an insulating base material. It is sometimes called as a component side.

21

SELF-CHECK KEY 2.1

Designing and Preparing PCB of AC-DC Power Supply

1. PCB 2. Substrate

3. Copper foil side 4. Epoxy

5. Phenolic

Note: If you got all the answers right, that is an excellent mark. But if you missed one or more, go back to the questions and study them more closely before you proceed to the next lesson .

22

OPERATION SHEET 2.1

Designing and Preparing PCB of AC-DC Power Supply Direction: Given the resources needed, perform the procedure in

designing and preparing a PCB of AC-DC Power Supply. Conditions

The following resources are needed: - Electronic tools and equipment

 Soldering Iron  Desoldering tool

 Screwdriver (Flat / and Philip)  Wire stripper / Utility knife  Pliers

 Diagonal cutter  long nose plier

 High grade magnifying glass with lamp  Cleaning brush  Soldering lead  Cleaning agent  Wires  Stranded  Solid

 Pre-design Printed Circuit Boards (PCB)

 Mini drill with drill bit ) with adaptor (+12VDC supply)  Sand paper

 Metal polish or eraser  Ruler

 AC-DC power supply kit (1.5 – 12 volts variable power supply)  Analog multi tester (voltmeter / VOM)

Procedure in Preparing the Layout Diagram in the PCB 1. Prepare the schematic diagram of the circuit.

23 2. Arrange the component circuit in a graphing paper to show/illustrate the same design factor in PCB lay outing. Note: Actual size of the component should be adapted for component arrangement and mounting.

ccc

PCB Layout

3. Interconnect each component by copying the connection in the schematic diagram.

Schematic Diagram

4. Double-check the connection.

5. Trace the designed PCB by using a carbon paper and mark it on the copper side of the clad board.

6. And use a high point permanent marker for marking. Do the marking three times and be careful not to shorten each line marking.

Capacitor Resistor Four Diodes AC Input DC Output Led Hole for Bolt & Nut

24 Characteristics of Good PCB Design – 4C’s

1. Clean. It should be clean so that the representation of the schematic diagram is easy to mark and troubleshoot the PCB.

2. Compressed. Reducing the size for space saving in chassis.

3. Creative in Design. There is a pattern or image when it is created. 4. Consistency in Component. The components should be well arranged

25

PERFORMANCE CHECK 2.1

Designing and Preparing PCB of AC-DC Power Supply

Direction: Answer the following by putting a check mark in the appropriate box.

Did you: YES NO

1. Prepare the schematic diagram of the circuit?

2. Arrange the components in the circuit in graphic paper to follow the design factor in PCB layout?

3. Interconnect each component? 4. Trace the design?

5. Produce a good characteristics PCB design (clean,

compressed, creative and consistent with the component size?

5 Yes Remarks 4 Yes Remarks Excellent Very Satisfactory

3 Yes Remarks 1-2 Yes Remarks

Satisfactory Needs Improvement

Student’s Signature______________________ Date ______________

26 INFORMATION SHEET 2.2

Printed Circuit Board Etching

It is the removal of unwanted portion or layer of conductive materials (that is copper) bonded to an insulating base called substrate. By using a chemical reaction to the copper called ferric chloride, it liquefies the uncovered surfaces of the designed copper clad board that creates a PCB.

Printed Circuit Board

Printed Circuit Board

Tools and Materials Needed In PCB Etching 1. Designed PCB

2. A bottle of the Ferric Chloride. (The quantity of bottle will depend upon the area of the PCB).

3. Plastic Basin. It is the medium of ferric chloride

4. Popsicle sticks (2 pieces). It is used for hauling the designed PCB.

5. Old newspaper. It is placed under the plastic basin for the prevention of accidental spill of chemical over the table.

6. Apron

7. Piece of Cloth

8. Plastic Varnish 1 bottle 9. Lacquer Thinner 10. Surgical Gloves 11. Knife or Cutter JOB SHEET 2.1 Cover Surface Copper Conductor Substrate Cover Surface Copper Conductor Substrate

27

Printed Circuit Board Etching

Direction: Given the resources needed, perform the procedure in PCB Etching to produce a PCB.

Conditions

The following resources are needed:  Electronic tools and equipment

- Soldering Iron - Desoldering tool

- Screwdriver (Flat / and Philip) - Wire stripper / Utility knife - Pliers

 Diagonal cutter  long nose plier

- High grade magnifying glass with lamp - Cleaning brush - Soldering lead 60/40 - Cleaning agent - Wires  Stranded  Solid

- Pre-design Printed Circuit Board (PCB)

- Mini drill with drill bit ( .9mm and 3mm ) with adaptor (+12VDC supply)

- PCB copper foil cleaning agent ( metal polish/Eraser ) - Pencil

- Ruler

- AC-DC power supply kit (1.5 – 12 volts variable power supply) - Analog multi tester (voltmeter / VOM)

Steps in PCB Etching

1. Prepare the necessary tools and materials needed in PCB etching.

2. Wear your apron and surgical gloves in order to prevent accidental splash of the solution on your clothes or on your skin.

28 3. Pour the ferric chloride in the plastic basin.

4. Etch the PCB by immersing it in a basin filled with ferric chloride until the uncovered part of the copper clad is totally etched.

5. After 10 - 15 minutes, check the PCB if all the parts needed to be removed are totally etched (using the two popsicle sticks in hauling). If not yet, return it into the plastic basin filled with ferric chloride. After 3 – 5 minutes check it again.

6. Haul the PCB from the plastic basin and wash it in a free flowing water to remove the remaining residue in the PCB.

PCB basin Plastic Basin Ferric Chloride Immerse PCB in plastic basin filled with ferric chloride

29 7. With a clean and dry piece of cloth, wipe the wet PCB.

8. Pour a little amount of lacquer thinner on a clean dry piece of cloth and wipe the markings of the permanent marker pen in the copper clad. (Note: In doing this, you should wear your surgical gloves.)

9. Aided by bright light, inspect the PCB for possible hairline break or short. If there is a hairline path between the copper conductors, cut it by a knife or cutter. And if there is a break between the copper conductors, solder it.

10. Apply plastic varnish to the newly etched PCB to prevent corrosion or rust, and let it dry before touching it.

light

PCB

30 Techniques to correct PCB Hairline Break or Short

A. Hairline Break. It is an open copper foil in the Printed Circuit Board. Most of the time this is due to improper PCB designing or etching. To eliminate the hairline break, just place a hook up wire and solder it.

Hairline Break

B. Hairline Short in the PCB Conductor. It arises if the printed circuit board designing or etching is done improperly. To eliminate the hairline short, you should cut it with a knife.

Hairline Short in the PCB Conductor Hairline Short

31 ASSESSMENT CHECKLIST 2.1

PCBEtching

Direction: Encircle the number which will show how competent you have applied the skill using the criteria below. Compute for the total result.

Criteria

Points

Final

Workmanship

Use of Tools

Use Personal Protective

Equipment

SPEED

House Keeping

Finished Design

Total

Assessment Criteria 2.1

Score Descriptive Grade

96-100 Excellent

86-95 Very good

81-85 Good

75-80 Fair

32 ASSESSMENT GUIDE FOR JOB SHEET 2.1

Direction: Encircle the number which shows how competent you have applied the skills according to the criteria given below.

The evidence shows that you have performed

the following: Points

Final Score 1. Prepared Printed Circuit Board design and

etch AC-DC power supply .

2. Mounted and soldered electronic components at the appropriate location on the Printed Circuit Board.

3. Interconnected all auxiliary components including the transformer on the Printed Circuit Board.

TOTAL

Rating System 2.1

Score Descriptive Grade

15 Excellent

12-14 Very good

10-11 Good

7-9 Fair

6 and below Reread the information sheet 2.2 on PCB Etching

33 OPERATION SHEET 2.3

Boring

Direction: Given the resources needed, perform the procedure in designing and preparing a PCB of AC-DC power supply.

Conditions

 Tools and Materials - Mini Drill - PCB - Piece of wood - Drill bit - Varnish Procedure

 Mini Drill Setup

1. Loosen the chuck by using a long metal tool and change the drill bit. This is done in a counter clockwise movement.

2. Insert the drill bit 1mm diameter in size and attach it to the chuck of the unit.

Mini Drill

Long Metal

Tool

34 3. Turn the long metal tool clockwise to tighten the jaw of the unit. Be sure that the drill bit is well secured on the chuck.

4. Before inserting the 12 volts adaptor, you should turn off the unit. 5. Test the rotation of the unit if it is well aligned. If not, align it

following the steps no. 1 and 2.

 How to Use a Mini Drill?

To control the unit, hold the mini - drill at the lower part and firmly position your arm. Then with the mini drill held perpendicularly to your work surface, lightly press downward to the holes to be drilled in the PCB but be sure that the PCB has a piece of wood under it to avoid damaging the table. With practice, you will be able to get the procedure correctly.

PCB

Mini Drill

35  Boring Procedure

1. Prepare all the materials needed. - Mini drill

- Designed PCB

2. Mark where the holes are to be drilled.

3. Using the mini drill, bore hole perpendicularly to the surface of the PCB.

4. Clean the surface of the PCB and look for open line or short circuit.

36 SCORING RUBRICS FOR OPERATION SHEET 2.3

Boring

Note: You should read the following before and after performing the process. Workmanship 55%

1. Tools were properly used according to its function. 25 2. PPE was observed completely while working. 25 3. Proper tools were used and PPE were observed while working. 5 Speed 5%

Finished task before time frame 5

Finished task within the time frame 4

Finished task 15 minutes after the time frame 3 Finished task 30 minutes after the time frame 2

Finished task 31 minutes and more 1

Housekeeping 5%

1. The whole area was cleaned after the assembly 5 2. The whole area was dirty after the assembly 1 Finished Design 35%

 Finished design based from the given

schematic diagram 35

 Finished design was correct but with access copper

clad on the finished design 30

 Finished design was correct but with cut on the line 25  Finished design was with shorted line that will cause

a short circuit 10

 Finished design was incorrect 2

Total 100%

Rating System

Score in Percent Descriptive Grade

95% - 100% Outstanding

80% - 94% Very Satisfactory

75% - 79% Satisfactory

74% and below Needs Improvement

Note: If you got 74 and below, you need to go over the procedures and ask assistance from your classmates who passed this activity or from your teacher.

37 JOB SHEET 2.2

Mounting and Soldering AC-DC Power Supply Project

Direction: Using the given tools, supplies and materials, mount the electronic components to the PCB and perform soldering procedure to

assemble an AC-DC power supply project. Conditions

o Supplies and Materials - Designed PCB

- Soldering Lead, 60/40 - AC cord with plug - Toggle Switch (on/off) - Fuse and fuse holder (1A)

- Selector switch – 2 poles 6 positions - 4 pcs. Rectifier diode

- Electrolytic capacitor – 3,300 uF/25V - Jumbo LED with holder

- Transformer, Primary voltage 0-220 volts; Secondary voltage (0V, 3V, 4.5V, 6V, 9V, 12V; current rating 750mA)

o Tools and Equipment - Long nose pliers - Soldering iron

 Simple Power Supply Project

In all the basic electronic theories, power supply assembling is the most common application needed by the students. In this project, they will be able to apply all the knowledge they have learned since the very start of their lessons. This project will enable them to practice the five characteristics of a good assembler. These are the planning, assembling, testing, troubleshooting and appreciating the work.

38 Schematic Diagram of a Multi-Volts Unregulated Power Supply

 Auxiliary Components of Power Supply

There are some minor components needed to be familiarized with and their uses. These are the AC plug with cord, power switch, fuse holder and fuse, selector switch, selector knob, indicator lamp and alligator clips.

- AC Plug with Cord is used for connecting the 220V input voltage of the power supply.

- Power Switch is used to control the flow of 220VAC to the power supply by turning off or on.

- Fuse Holder & Fuse is used to protect the unit from any sudden short from the load or too much rising of power from the line source.

- Selector Switch is used to select the output voltage of the power supply from 3V to 12V DC

- Selector Knob is a plastic holder of the selector switch.

- Indicator Lamp is used to show if there is a presence of power in the circuit.

Neon Lamp is for 220V AC monitoring lamp. Led is for output monitoring lamp

- Alligator Clips are used to connect the two-line output to the load. Red clip for positive.

39

Sample Components Placement Guide

cc

c

Top View of PCB Layout

PCB LAYOUT Procedure:

1. Prepare all the materials needed.

2. Clean the terminals of the components to be soldered and the PCB copper side.

3. Mount the components in the PCB. 4. Solder components.

5. Cut the excess terminals of the component. 6. Test the circuit using the multi-tester.

Four Diodes AC Input DC Output Led Hole for Bolt & Nut

40 ASSESSMENT CHECKLIST FOR JOB SHEET 2.2

Mounting and Soldering AC-DC Power Supply Project

Direction: Encircle the number which will show how competent you have applied the skill using the criteria given below. Compute for the total result.

Criteria

Points

Final

Workmanship

Use of Tools

Use PPE

SPEED

House Keeping

Finished Design

Total

Assessment Criteria 2.3

Score Descriptive Grade

96-100 Excellent

86-95 Very good

81-85 Good

75-80 Fair

41

ASSESSMENT PLAN

Evidence Checklist

Competency standard CONSUMER ELECTRONIC SERVICING NC II

Unit of competency ASSEMBLE AND DISASSEMBLE CONSUMER _{ELECTRONIC PRODUCTS AND SYSTEMS} Title of Module ASSEMBLING AC-DC POWER SUPPLY

Ways on how evidences will be collected

[tick the column]

Obse rv at io n Or al Qu es tio n ing Third part y R epo rt Dem ons trat io n Por tf ol io W ri tt en

The evidence shows that the student can…

 identify types of power supply

 identify parts of AC-DC power supply

 identify electronic components needed in assembling AC- DC power supply

 prepare, design and etch printed circuit board of an AC-DC power supply.

 mount and solder electronic components at the appropriate location on the printed circuit board.

 interconnect the PCB with all the auxiliary components.

 securely mount all the components at the chassis

 correct all defects of an AC-DC power supply .

Did the student’s overall performance meet the standard? Yes No

Prepared by: Date:

42

OBSERVATION CHECKLIST

Student’s name: Teacher’s name: Name of School Competency standards Unit of competency:

Instructions for the teacher:

1. Observe the student in Assembling AC-DC power supply

2. Describe the assessment activity and the dates when it will be undertaken 3. Place a tick in the box to show that the student has completed each aspect of

the activity according to the standard expected in the enterprise. 4. Complete the feedback sections of the form.

Date of observation

Description of assessment activity

Location of assessment activity

The student has: If yes, tick the box

 Identified types of power supply

 Identified parts of AC-DC power supply

 Known the electronic components in assembling AC-DC power supply.

 Prepared, designed and etched printed circuit board of an AC-DC power supply.

 Mounted and soldered electronic components at the appropriate location on the printed circuit board.  Interconnected the PCB with all auxiliary components.  Securely mounted all components at the chassis.  Corrected all defects of an AC-DC power supply.

Did the student’s overall performance meet the standard?

Yes No

Teacher’s Feedback

43

OBSERVATION AND QUESTIONING CHECKLIST

Student’s name Teacher’s name Name of School Competency standards Unit of competency

Instructions for the teacher:

1. Observe the candidate in Assembling AC-DC power supply

2. Describe the assessment activity and the date when it will be undertaken. 3. Place a tick in the box to show that the student has completed each aspect of the activity according to the standard expected in the enterprise.

4. Ask the student based on the questions in the list to confirm his/her underpinning knowledge

5. Place a tick in the box to show that the student has answered the questions correctly.

6. Complete the feedback sections of the form.

Date of observation

Description of assessment activity

Location of assessment activity

The student has If yes, tick the box

 Identified types of power supply.

 Identified parts of AC-DC power supply

 Known electronic components needed in assembling AC-DC power supply.

 Prepared, designed, and etched Printed Circuit Board of an AC-DC power supply.

 Mounted and soldered electronic components at the appropriate location on the printed circuit board.  Interconnected the PCB with all the auxiliary

components.

 Securely mounted all the components at the chassis.  Corrected all defects of an AC-DC power supply

Yes No

Did the student’s overall performance meet the standard?

44

DEMONSTRATION

Student’s name: Teacher’s name: Unit of competency: Competency standards: Date of assessment: Time of assessment:

Instructions for demonstration

Given the necessary materials the trainee/student must be able to:

Materials and equipment:

 to show if the skill has demonstrated

During the demonstration of skills, did the

student: Yes No N/A

 Identify types of power supply?







 Identify parts of AC-DC power supply?







 Know the electronic components needed in

assembling AC-DC power supply?







 Prepare, design and etch printed circuit board of

an AC-DC power supply?







 Mount and solder electronic components at the appropriate location on the printed circuit

board?







 Interconnect the PCB to all the auxiliary

components?







 Securely mount all components at the chassis?







 Correct all defects of an AC-DC power supply ?







The student’s demonstration was:

45

WRITTEN REPORT

Student’s name: Teacher’s name: Name of School Competency standards Unit of competency: Task:

Your task is to:

 Assemble AC-DC power supply

Submission date:

Use the checklist below as the basis for judging whether the student’s report has met the required competency standards.

The student’s report states that If yes, tick the box

 The types of power supply were identified.

 The parts of AC-DC power supply were identified.  The electronic components needed in assembling AC-DC

power supply were identified.

 The printed circuit board of an AC – DC power supply was prepared, designed and etched.

 The electronic components mounted and soldered at the appropriate location on the printed circuit board.

 The PCB was interconnected to all auxiliary components.  All the components were securely mounted at the

chassis.

 All defects of an AC-DC power supply were connected. Generally, did the student’s report meet the

standard? Yes No Comments: Student’s signature: Date: Teacher’s signature: Date:

46

PERFORMANCE TEST

Student's Name Date

Competency: Test Attempt

1st 2nd 3rd

Directions:

Ask your teacher to assess your

performance in the following critical tasks using the performance criteria below.

You will be rated based on the overall evaluation at the right side.

OVERALL EVALUATION

Level

Achieved PERFORMANCE LEVELS

4 - Can perform this skill without direct

supervision and with initiative and adaptability to problem situations.

3 - Can perform this skill satisfactorily without direct assistance or supervision.

2 - Can perform this skill satisfactorily but requires some assistance and/or supervision. 1 - Can perform parts of this skill satisfactorily, but requires considerable assistance and/or supervision.

Teacher will put initial at level achieved.

PERFORMANCE STANDARDS

For acceptable achievement, all items should receive a

"Yes" or "N/A" response. Yes No N/A

 Types of power supply were identified.

  

 Parts of AC-DC power supply were identified.

  

 Electronic components needed in assembling AC-DC power

supply were identified.

  

 Printed Circuit Board of an AC – DC power supply was prepared,

designed and etched.

  

 Electronic components were mounted and soldered at the

Appropriate location on the Printed Circuit Board

  

 The PCB was interconnected with all the auxiliary components.

  

 All components were securely mounted at the chassis.

  

 All defects of an AC-DC power supply were corrected.

  

REFERENCES

1. Tan, Michael Q., Gantalao, Fred T., Lasala, Rommel M. Simple Electronics; Andes Mountain Printers: 2004

2. Enriquez, Marcelo T. Electronics Technology IV; Souvenir Publications, Inc.: 2003

ACKNOWLEDGMENT

Copyright Department of Education 2008 First Published JUNE 2008

This module is based on the Competency-Based Curriculum-Contextual Learning Matrix (CBC-CLM) and finalized on the Instructional Modules Finalization Development Workshop conducted at the Finalization Workshop conducted at the Development Academy of the Philippines, Tagaytay City on May 6 -10, 2008

This learning instrument was developed by the following personnel: Technology Teachers:

 Mr. Vic P. Diola – Group Leader Bauan Technical High School

 Dr. Gilbert M. Castor

Don Alejandro Roces Sr. Science-Technology High School  Mr. Eddielou L. Dayao

Sanchez Mira School of Arts and Trades  Mr. Rufo G. Malla

Eulogio Rodriguez Vocational High School  Mr. Sherwin P. Medrano

San Pedro Relocation Center National High School  Mr. Remar C. Pinsoy

Baguio National School of Arts and Trades Contextual Teacher:

Mrs. Daisy Carousel P. Cervantes

Don Alejandro Roces Sr. Science-Technology High School Facilitators:

 Dr. Edward M. Dela Rosa  Dr. Corazon L. Echano

TEC-VOC Task Force Encoders:

 Mrs. Rosario D. Briones  Mr. Mhariel L. Echano  Mr. Jason O. Villena

ACKNOWLEDGEMENT

Copyright: Department of Education 2009

This module is based on Competency-based Curriculum- Contextual Learning Matrix ( CBC-CLM ) refined during the Writeshop on the Refinement and Enrichment of Competency-Based Curriculum and Contextual Learning Matrix of ARTS and TRADES Specializations at Marikina Hotel, Marikina City on April 20 – 25,2009.

This learning instrument was refined and enriched by the following educators:

Technology Teachers ( Electronics )

VICTORINO P. DIOLA – Group Leader

TVE Coordinator, Bauan Technical High School Bauan, Batangas

GIGI C. CORPUZ

Teacher III, Malvar National High School Malvar, Batangas

ISMAEL G. GALLARDO

Teacher I, Community Vocational High School Masipit, Calapan City, Oriental Mindoro

REYNALDO C. CUNANAN

Head Teacher VI, EARIST Voc. High School Nagtahan, Sampaloc, Manila

GEORGE B. FUASO

Teacher II, Gen. Mariano Alvarez Technical High School GMA, Cavite

RUFO G. MALLA

Teacher II, EARIST Voc. High School Nagtaha, Sampaloc, Manila

Contextual Teachers: English

TERESITA P. TANAEL

Teacher III, Gen. Mariano Alvarez High School GMA, Cavite

CHARLIE I. SORIANO

Mathematics

ANALISA ROSA P. LIBRADA

Teacher I, Mathematics Coordinator

San Pedro Relocation Center National High School San Pedro, Laguna

Science

GEMMA G. VALLARTA

Teacher III, Science Coordinator

San Pedro Relocation Center National High School San Pedro, Laguna

LENALYN N. MANZANO Teacher I, Physics

E. Rodriguez Vocational High School Nagtahan, Sampaloc, Manila

Facilitators:

Dr. CORAZON L. ECHANO Tech-Voc Task Force

Dr. VICTORIO N. MEDRANO Tech-Voc Task Force

Dr. ORLANDO E. MANUEL Tech-Voc Task Force

Encoder:

MARISOL E. SALDIVAR

Teacher I, Sta. Lucia High School Pasig City

Unit of Competency: MAINTAIN AND REPAIR CONTROLLED DOMESTIC APPLIANCES

Module No. 2

MAINTAINING AND REPAIRING AN ELECTRIC FAN

Republic of the Philippines Department of Education PUBLIC TECHNICAL -VOCATIONAL

Table of Content

How to Use this Module ... 2 Introduction ... 3 Technical Terms ... 4 Learning Outcome 1:

Identify the parts and functions of an electric fan ... 6  Learning Experience / Activities ………..7  Information Sheet 1.1 ... 8  Student-Check 1.1... 11  Answer Key 1.1 ... 12 Learning Outcome 2:

Diagnose an electric fan and troubleshoot the defects found ... 13  Learning Experience / Activities ………...14  Operation Sheet 2.1 ... 15  Performance Test 2.1 ... 23  Student Write-up A ... 23

 Student Write-up A ……….24

Learning Outcome 3:

Maintain and repair an electric fan... 25  Learning Experience/Activity ………..26  Information Sheet 3.1 ... 27  Student Check 3.1 ... 31  Student Check Key 3.1 ... 32  Job Sheet 3.1 ... 33 Performance Test ... 35 Assessment Plan ... 36 Observation Checklist for Performance test ... 37 Questionnaire Checklist ... 38 Observation Checklist 3.1 ………39 Questioning Checklist ………40 Acknowledgement……….42

2

HOW TO USE THIS MODULE

Welcome to the Module “Maintaining And Repairing An Electric Fan”. This module contains training materials and activities for you to complete.

The unit of competency “Maintain & Repair Electronically-Controlled Domestic Appliances” contains the knowledge, skills and attitudes required for Consumer Electronics Servicing required 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 and Activity Sheets. Do these activities on your own and answer the Self-Check at the end of each learning activity.

If you have questions, don’t hesitate to ask your teacher for 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; and have already completed training in this area.

If you can demonstrate competence to your teacher in a particular skill, talk to him/her 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 consistent with and 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 Maintaining and Repairing an Electric Fan independently at your own pace with minimum supervision from your teacher.

3 Program/Course: CONSUMER ELECTRONIC SERVICING NC II

Unit of Competency: MAINTAIN AND REPAIR ELECTRONICALLY-_{CONTROLLED DOMESTIC APPLIANCES}

Module Title: MAINTAINING AND REPAIRING AN ELECTRIC FAN INTRODUCTION:

This module contains information and suggested learning activities in maintaining and repairing an electric fan. It covers the knowledge, skills and attitudes required to maintain and repair an electric fan.

Completion of this module will help you better understand the succeeding module on maintaining and repairing electronically-controlled domestic appliances.

This module consists of three (3) 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 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 functions of an electric fan;  LO2. diagnose and troubleshoot an electric fan; and  LO3. maintain and repair an electric fan.

4 TECHNICAL TERMS

AC Motor. It converts AC electrical energy into mechanical energy producing a mechanical rotary action that performs some kind of work.

Antistatic. It is a container which resists generation of triboelectric charge (frictionally generated ) as the device is inserted into, removed from , or allowed to slide around it.

Bushing. It is a sleeve protecting a conductor where it passes through a hole in motor.

Capacitor. It is a device used to boost the voltage to a motor. Running

capacitors are used in the starting winding to increase the running torque of the motor. Starting capacitors are used in the starting winding to increase the starting torque of the motor.

Capacitor for Start Motor. It is a low reactance non-polar electrolytic capacitor connected in series with the start winding.

Motor. It is a rotating electric machine which changes applied electrical energy or power into mechanical output energy or power.

Rotor. It is the part of an electric motor that turns or rotates.

Run Winding. It is the winding in an electric motor provides the power for turning the rotor during operation. It has the larger wire of the two windings. The main winding of the motor is comparatively low resistance and high inductance.

Rectifier. It is a diode circuit that converts AC to pulsating DC.

Resistor. It is a component made of material that opposes the flow of current and therefore has some value of resistance.

Rotary Switch. It is an electromechanical device that has a rotating shaft connected to one terminal capable of making, breaking a connection to one or more other terminals.

Shaft. It is the part of a rotor that carries other rotating members and that is supported by bearings in which it can rotate.

Start Winding. It is the auxiliary winding of the motor with comparatively high resistance and lower inductance.

Stator. It is the stationary part of the motor which the field windings are placed.

5 System Control Microprocessor. It is an integrated circuit that can recognize

and respond to commands from the operator by monitoring the DC voltages at the output terminals.

Schematic Diagram. It is an illustration of an electrical or electronic circuit with the components represented by their symbol.

Short Circuit. It is also called as short. It is low resistance connection between two points in a circuit typically causing excessive current.

Solder. It is a metallic alloy used to join two metal surfaces.

Soldering. It is a process of joining two metallic surfaces to make an electrical contact by melting solder (tin and lead) across them.

Substrate. It is a mechanical insulating support upon which a device is fabricated.

Switch. It is an electrical device having two states, ON (closed) or OFF (open). Thermal cutout. It is an over current device that contains a heater element in

addition to and affecting a renewable fusible member which opens the circuit. It is not designed to interrupt short-circuit currents. Transformer. It is an inductor with two or more windings.

Troubleshooting. It is a systematic approach to locate the cause of a fault in an electronic circuit or system.

Winding. It is an assembly of coils designed to act in consort to produce a magnetic flux field or to link a flux field.

6 Program/Course CONSUMER ELECTRONIC MECHANIC NCII

Unit of

Competency MAINTAIN AND REPAIR ELECTRONICALLY-CONTROLLED DOMESTIC APPLIANCES

Module Title MAINTAINING AND REPAIRING AN ELECTRIC FAN Learning Outcome 1: Identify the parts and functions of an electric fan.

Assessment Criteria:

1. The operation of an electric fan is explained. 2. The parts of an electric fan are identified. 3. The functions of its parts are explained.

7 LEARNING EXPERIENCE / ACTIVITIES

Learning Outcome 1 : Identify the functions of the parts of an electric fan.

Learning Activities Special Instructions Read the Information Sheet

1.1 on Operation of an electric fan, parts and its functions. Do the Self-Check No. 1.1 to check your knowledge on the Operation of an electric fan, parts and its functions.

Check your answers using the Answer Key.

If you were not able to answer all the questions, go over again to the Information Sheet. If you have answered all the questions, you can proceed to the next learning outcome.

You can ask assistance from your teacher to show you and explain to you further by the topics you don’t understand well.

Try to answer the Self-Check without looking at the

8

INFORMATION SHEET 1.1

Operation of an Electric Fan, Parts and Functions

OPERATION OF AN ELECTRIC FAN

Electric Fan is an air moving machine used to cool with an AC Motor connected to the 60 Hz power source which converts electrical energy to mechanical energy in order to generate a moving air. It is a power driven machine capable of providing high air flow parallel to the axis of the motor shaft where an axially mounted impeller or fan blade agitates the air. The air velocity/delivery of the electric fan is controlled by a mechanical speed selector switch for old models and electronically controlled speed selector switch for new models. Timer is also included for fully automatic operations.

PARTS OF AN ELECTRIC FAN

 Front Guard. It is a protective metal mesh wire used to prevent the fan blade from any physical contact with foreign

objects.

 Guard Mark. It is a logo of the manufacturer of the electric fan which is mounted at the center of the front guard.

9  Switch Box . It is a panel board for the controls of the electric fan.  Inner Pipe. It is a metal tube inserted into the outer tube intended

for the proper height adjustment of the electric fan.  Outer Pipe. It is a metal tube attached to the base stand of the

Electric fan.

 Base Stand. It is the bottom or lowest part of the electric fan where it stands on as a foundation.

 Blade. It is a propeller made out of plastic or metal attached to the motor shaft and agitates air when the motor rotates.

 Remote Control. It is a transmitter device used to control the electric

fan from a distance.

Block Diagram of Electronically-Controlled Electric Fan (ECEF)

 Power Controller. It is a circuit that controls the amount of power Supplied to the motor.

10  Sensor It is the input receiver that detects input signal

coming from remote control.

 Manual Control. It is a push button switch that controls manually operation of the electric fan.

 Non-polarized Capacitor. A low reactance non-polar capacitor

connected in series with the start winding of an electric fan.

 Timer. It is used to switch on or switch off automatically with predetermined time.

 Comparator. It is a processing circuit that accepts the input input signal coming from remote control, manual switch or timer switch. This circuit provides the triggering voltage to the power controller.

 AC Motor. It is rotating electric machine which changes applied electrical energy or power into mechanical output

energy or power.

 AC Plug. It is a connector intended for connecting to the main source 220 V.

11

SELF-CHECK 1.1

Direction: Label the different blocks that resemble an electronically-

controlled electric fan. Write your answer in piece of paper. Do not write anything in this module.

I

12

ANSWER KEY TO SELF-CHECK 1.1

I 1. Blade 2. Front Guard 3. Switch Box 4. Inner pipe 5. Base stand II 1. Comparator 2. Power Controller 3. AC Motor 4. Sensor 5. Manual Switch