ia- electronics lm grade 7 & 8 p&d

Table of Contents

LEARNING MATERIALS

ELECTRONICS

TLE-IA CONSUMER ELECTRONICS SERVICING Page 1

Table of Contents

I. INTRODUCTION 3

II. OBJECTIVES 4

III. PRE-ASSESSMENT 4

IV. LEARNING GOALS/TARGETS 5

V. COMMON COMPETENCIES

A. KNOW

Lesson 1. Occupational Health and Safety 6

Lesson 2. Introduction to Electricity 9

Lesson 3. Basic Structure of Matter 12

Lesson 4. Electric Charge 13

Lesson 5. The Valence Shell 15

Lesson 6. Electrical Current 17

Lesson 7. Voltage 19

Lesson 8. Resistance 20

B. PROCESS

Lesson 1. OHMs Law 23

Lesson 2. Complete Circuit 29

Lesson 3. Types of Circuit 34

Lesson 4. Circuit Diagrams 36

Lesson 5. Resistor 44

Lesson 6. Other Electronic Components 51

Lesson 7. Basic Hand Tools and Equiment 54

C. REFLECT AND UNDERSTAND

Lesson 1/Activity 1: Resistor Color Coding 71

Lesson 2/Activity 2: Proper Use of Soldering Iron 81

Lesson 3/Activity 3: Desoldering 87

Lesson 4/Activity 4: How to Use and Read a Multimeter 88

Lesson 4/Activity 5: Use the Right Tool for the Job 96

D. TRANSFER

Performance 1/Assessment 1:

Construction of Series Circuit 99


Construction of Parallel Circuit 107


Soldering Technique Using Wire 114


Soldering Components on PCB 117


Astable Multivibrator Using Transistor 117

VI. SUMMARY 122

VII. GLOSSARY 122

VIII. REFERENCES 123


I. INTRODUCTION

Your Technology & Livelihood Education (TLE) subject has four areas:

Information and Communication Technoloy (ICT), Home Economics (HE), Agri-

Fishery Arts (AFA) and Industrial Arts (IA). Consumer Electronics is a course under

Industrial Arts.

Electronics is a branch of physics that deals with the behavior and controlled

flow of electrons.

Have you ever been curious about what is inside an FM radio box? Will you be

able to identify the components present inside that box? So many small components

inside that box.

The voltage commonly used in home appliances is 220V (It varies from country

to country). 220 V is applied between the terminals of the primary coil of

transformer. A transformer has the capability to change high voltage to low voltage

and vice versa. It converts 220 V into low level voltage.

If you explore inside a computer, you will find many rectangular shaped

objects which have many vertical pins along the edges. Known as Integrated Circuits

(IC), these chips consist of many electronic components.


Consumer Electronics Servicing is a full course that leads to the National

Certificate Level II (NCII).CES is designed to enhance your knowledge, skills, and

attitudes as a trainee/student on core competencies of electronics such as

assembly/disassembly of consumer electronic products and systems, maintainance

and repair of audio/video products, electronically-controlled domestic appliances and

cellular phones in accordance with industry standards. It also includes basic

competencies such as, being able to participate in workplace communication, work

in team environment, practice career professionalism and practice occupational

health and safety procedures. This module will mainly focus on, only common

competencies such as: basic hand tools and equipment; maintaining hand tools and

equipment; performing mensuration and calculation; preparing and interpreting

schematic diagrams; and occupational health and safety will be introduced.

Career Oppurtunities

Service technicians are electronic home entertainment equipment installers and repairers; they can repairs a number of different products; among them are televisions and radios, stereo components, video and audio disc players, video cameras, video recorders and cellphones.


Smaller portable equipment and devices may be brought to repair shops for service by customers. The workers here, called bench or shop technicians, have on hand a wide variety of electronic tools and parts. Customers may request technicians to make house calls when bigger, not so portable equipment breaks down. The workers that typically make house calls are known as field technicians, and carry with them a small set of tools and spare parts in order to make repairs on-site for the customer. When field technicians run into a complicated jobs or problems, they may return to the shop with the faulty part in order to identify the problem and finish the repair there.

Growth in consumer electronics servicing as a career is expected to rise

steadily because repair is a lot cheaper than buying a new consumer product.

Furthermore, job opportunities are widely availlable both locally and abroad to those

who are knowledgeable and well experienced in this field.

II. OBJECTIVES

At the end of this module, you, as a learner, are expected to: 1. demonstrate understanding of the concepts and underlying principles of

process and delivery in using consumer electronics hand tools and equipment while observing occupational and safety practices.

III. PRE-ASSESSMENT

Direction: Match the different hand tools in column A with their actual pictures in

column B. Write the letter on the blank provided before each number.

A B ____1.Soldering iron A.

____2.Desoldering tool B.

____3.Soldering stand C.

____4. Long nose pliers D.


____5.Mini- drill E.

____6.Paint brush F.

____7. Blade cutter G.

____8. Side-cutter H.

____9. Wire splicer I.

____10. Magnifying glass J.

K.

IV. LEARNING GOALS/TARGETS:

Now that you have an idea of the coverage of this module, set your learning goal in terms of what you want to attain at the end of your lessons in Consumer Electronics Servicing. Next, specify this in terms of the following:

Goal: ____________________________________________

Targets:

a. What I want to know: _________________________ b. What I want to be able to do: ___________________ c. What I want to understand: _____________________ d. What I want to produce or understand: _____________

Start writing your own learning goals/targets on your notebook based on the

stated objectives.


V. COMMON COMPETENCIES

A. KNOW

Lesson 1. Occupational Health and Safety (OHS)

After reading this section you will be able to do the following:

Define occupational health and safety.

Value the importance of health and safety at work.

Occupational safety and health (OSH) is a cross-disciplinary area concerned with protecting the safety, health and welfare of people engaged in work or employment. The goals of occupational safety and health programs include fostering a safe and healthy work environment. OSH may also protect co-workers, family members, employers, customers, and many others who might be affected by the workplace environment.

Occupational safety and health are important for moral, legal, and financial reasons. Moral obligations involve the protection of employee's lives and health. Legal reasons for OSH practices relate to the preventive, punitive, and compensatory effects of laws that protect worker's safety and health. OSH can also reduce employee injury and illness related costs, including medical care, sick leave and disability benefit costs. OSH may involve interactions among many subject areas, including occupational medicine, occupational hygiene, public health, safety engineering, industrial engineering, chemistry, health physics, ergonomics, and occupational health psychology.


WORKSHOP SAFETY RULES

In any activity involving skills, it is a standard procedure to always use the

right tool or equipment properly in a particular task. In spite of this reminder or

caution, some students abuse the use of some tools and still commit errors that may

cause accidents. Below are safety rules to be observed in the workplace.

1. Always listen carefully to the teacher and follow instructions. 2. Do not run in the workshop, you could bump into another student and cause an accident. 3. Know where the emergency stop buttons/power switches are positioned in the workshop. If you see an accident at the other side of the workshop you can use the emergency stop button/power switches to turn off all electrical power to machines. 4. Always wear an apron as it will protect your clothes and hold loose clothing. 5. Wear good strong shoes. 6. When attempting practical work all stools should be put away. 7. Bags should not be brought into a workshop as people can trip over them. 8. When learning how to use a tool/machine, listen very carefully to all the instructions given by the teacher. Ask questions, especially if you do not fully understand the given instruction. 9. Do not use a tool/machine if you have not been shown how to operate it safely by the teacher. 10. Always be patient, never rush in the workshop. 11. Keep hands away from moving/rotating machinery. 12. Use hand tools carefully, keeping both hands behind the cutting edge. 13. Report any damage to tools, machines & equipment as this could cause an accident.

Suggested Activities:

For additional localized information regarding Occupational Health and Safety please download the NATIONAL PROFILE ON OCCUPATIONAL SAFETY AND HEALTH (PHILIPPINES) from http://www.oshc.dole.gov.ph or by using this shortcut link: http://cloud.eacomm.com/oshc2010/UserFiles/oshc2010/file/National-OSH-Profile.pdf.

The teacher may require the students to visit the following interactive sites.


Safety Check

Safety Check is an online Occupational Health and Safety (OHS) test designed for workers. Use this test to learn more about topics such as OHS laws; manual handling; hazardous substances; noise; mechanical equipment; and electricity.

Link:

http://203.147.178.216/safeworksa/EducationAndTraining/ActivitiesAndTests/SafetyCheck/default.asp

Virtual Office

Working in the office environment may not be as safe as you think! A test of safety knowledge designed for students and young workers, or workers who may need reminding to be alert for hazards in the workplace.

Link:

http://www.safework.sa.gov.au/contentPages/EducationAndTraining/ActivitiesAndTests/VirtualOffice/vofficeframe.htm

10 Commandments of Workplace Safety

http://www.youtube.com/watch?v=08yxsNnzwnY&feature=related

Question:

What is occupational health and safety? Give its importance to a healthy working

environment.

Sample Scoring Criteria

Beginning

(1)

Developing

(2)

Approaching

Proficiency

(3)

Proficient

(5)

Organization Unclear flow of

ideas.

Some signs of

and/or abrupt

change of

ideas.

Some ideas

and sequence

may be

improved.

Sequence and

transition of

ideas was

effective.


Details Inappropriate

/off-topic

Too general. Contained

some

appropriate

details or

examples.

Convincingly

interpreted.

Sample Rating Scale:

Points earned Equivalent Percentage

10 100

9 97

8 93

7 90

6 86

5 83

4 79

3 76

2 72

1 69

0 65

Lesson 2. Introduction to Electricity


Define electricity and identify the origin of the term. Discuss how electricity can be observed in the world.

What is Electricity?

Electricity is a naturally occurring force that exists all around us. Humans have been aware of this force for many centuries. Ancient man believed that electricity was some form of magic because they did not understand it. Greek philosophers noticed that when a piece of amber was rubbed with cloth, it would attract pieces of straw. They recorded the first references to electrical effects, such as static electricity and lightning, over 2,500 years ago.


It was not until 1600 that a man named Dr. William Gilbert coined the term electrica, a Latin word which describes the static charge that develops when certain materials are rubbed against amber. This is probably the source of the word electricity." Electricity and magnetism are natural forces that are very closely related to one another.

Watch this 5 minute video about electricity for additional information and knowledge.

http://www.youtube.com/watch?v=WbNjrKtR0BY&feature=related

Review

1. Electricity is a naturally occurring force that exists all around us. 2. Electricity comes from electrica, a Latin word which describes the static

charge that develops when certain materials are rubbed against amber. 3. Electricity gives a wide variety of well-known effects, such as lightning & static

electricity.


Lesson 3. Basic Structure of Matter


Give a basic definition of matter. Describe a molecule. Differentiate an element and a compound.

All matter such as solids, liquids, and gases, is composed of atoms. Therefore, the atom is considered to be the basic building block of matter. Moreover, atoms are almost always grouped together with other atoms to form what is called a molecule. Only a few gases such as helium are composed of individual atoms as the structural unit.

Atoms are extremely small and cannot be seen by our naked eyes.

Any material that is composed of only one type of atom is called a chemical element, a basic element, or just an element. Any material that is composed of more than one type of atom is called a compound.

Water is a compound made from the elements hydrogen and oxygen.

Activity 1. Fill-in the Missing Word. Directions: Supply the necessary word or group of words that will make the sentence complete. 1. Matter is composed of _________. 2. A group of atoms is called _________. 3. A material which composed of only one kind of atom is called _______. 4. _____________ is a material composed of more than one kind of atom.


Activity 2. Water Molecule Directions: On an Oslo Paper draw the water molecule.

Review

1. Matter is composed of atoms. 2. A molecule is a group of atoms grouped together 3. An element is a material composed of only one kind of atom while a

compound is a material composed of more than one kind of atom.

Lesson 3. Basic Structure of an Atom


Describe the basic structure of an atom. Explain what holds an atom together.

What is an atom composed of?

An atom is the smallest particle of any element that still retains the characteristics of that element. However, atoms consist of even smaller particles. Atoms consist of a nucleus that is surrounded by one or more negatively charged particles called electrons. The nucleus is made up of positively charged particles called protons and neutrons which are neutral. An atom is held together by forces of attraction between the electrons and the protons. The neutrons help to hold the protons together.

Hydrogen Atom

Niels Bohr was a Danish scientist who introduced the model of an atom in 1913. Bohr's model consists of a central nucleus surrounded by tiny particles called electrons that are orbiting the nucleus in a cloud. In our pictures and


exercises, the electron appears to orbit in the same path around the nucleus much like the planets orbit the Sun. The electrons, however do not really orbit in the same path. The electrons actually change their orbit with each revolution.

Review

1. Atoms are composed of protons, neutrons, and electrons. 2. The forces of attraction between the electrons and the protons hold an atom

together.

Activity: The Hydrogen Atom Directions: On an Oslo Paper draw the water molecule.

Lesson 4. Electric Charge


Explain the differences between electrons and protons. Predict what happens when protons and electrons interact with other protons

or electrons.

Electrons are the smallest and lightest of the particles in an atom. Electrons are in constant motion as they circle around the nucleus of that atom. Electrons are said to have a negative charge, which means that they seem to be surrounded by an electrostatic field.


Protons are much larger and heavier than electrons. Protons have a positive electrical charge. This positively charged electrostatic field is exactly the same strength as the electrostatic field in an electron, but it is opposite in polarity. Notice that the negative electron (pictured at the top left) and the positive proton (pictured at the right) have the same number of force field lines in each of the diagrams.

Like charges repel, unlike charges attract

Two electrons will tend to repel each other because both have negative electrical charge. Two protons will also tend to repel each other because they both have positive charge. On the other hand, electrons and protons will be attracted to each other because they have unlike charges.

Repel

Repel

Attract

Another important fact about the electrical charges of protons and electrons is that the farther away they are from each other, the less force their electric fields have on each other. Similarly, the closer they are to each other, the more force they will experience from each other due to this invisible force field called an electric field.

Activity: Repel or Attract Direction: Based on your observation, write whether the following magnet instances repel or attract each other.

INSTANCES

________1.

________2.

________3.

________4.


Review

1. Electrons have a negative electrostatic charge and protons have a positive electrostatic charge.

2. A good way to remember what charge protons have is to remember both proton and positive charge start with P.

3. Like charges repel, unlike charges attract, similar with magnets.

Lesson 5. The Valence Shell


Define valence shell. Explain what free electrons are and why they are important.

What is the valence shell?

Notice that in the copper atom pictured below that the outside shell has only one electron. This represents that the copper atom has one electron that is near the outer portion of the atom. The outer shell of any atom is called the valence shell. When the valence electron in any atom gains sufficient energy from some outside force, it can break away from the parent atom and become what is called a free electron.

Pictured here is an atom of copper, which is much more complex than either an atom of hydrogen or helium.

Atoms with few electrons in their valence shell tend to have more free electrons since these valence electrons are more loosely bound to the nucleus. In some materials like copper, the electrons are so loosely held by the atom and so close to the neighboring atoms that it is difficult to determine which electron belong to which atom. Under these conditions, the valence or free electrons tend to drift randomly from one atom to its neighboring atoms. Under normal conditions the movement of the electrons is truly random, meaning they are moving in all directions by the same amount. However, if some outside force acts upon the material, this flow of electrons can be directed through materials and this flow is called electrical


current. Materials that have free electrons and allow electrical current to flow easily are called conductors. The top three best conductors of electricity are Silver, Copper and Gold. Many materials do not have any free electrons. Because of this fact, they do not tend to share their electrons very easily and do not make good conductors of electrical currents. These materials are called insulators, examples are rubber, plastic and glass.


Crossword Puzzle Direction: Complete the crossword by filling in a word that fits each clue. Clues

Review

1. The valence shell is the outer shell of the atom. 2. Some materials have a free electron in their valence shell and this electron

can easily move from atom to atom. 3. The free electrons are responsible for electrical current. 4. Conductors are materials that allow the electrical current to flow easily. 5. Insulators are materials that do not allow the electrical current to flow easily.

Lesson 6. Electrical Current After reading this section you will be able to do the following:

Define amperes. Identify the instrument that is used to measure amperage.

Electricity refers to the energy produced (usually to perform work) when

electrons are caused to flow directionally from atom to atom. This movement of electrons between atoms is called electrical current.


Electricity can be very dangerous. It is important to know

how it behave in order to work with it safely. The flow of electrons is measured in units called amperes.

An ammeter is an instrument used to indicate how many amps of current are

flowing in an electrical circuit. Open Circuit

Closed Circuit


Review

1. Amperage is a term used to describe the number of electrons moving past a fixed point in a conductor in one second.

2. Current is measured in units called amperes or amps 3. An Ammeter is used to measure amperage.

Lesson 7. Voltage


Define electromotive force (EMF) and explain how it is measured. Explain why EMF is important to the flow of electrical current. List several examples of sources of electromotive force.

The force that causes the electrons to move in an electrical circuit is called electromotive force (EMF). This force is called electromotive force, or EMF. Sometimes it is convenient to think of EMF as electrical pressure. In other words, it is the force that makes electrons move in a certain direction within a conductor.

But how do we create this electrical pressure to generate electron flow? There are many sources of EMF. Some of the more common ones are batteries, generators, and photovoltaic cells, just to name a few.

Batteries are constructed so there are too many electrons in one material and not enough in another material. The electrons balance the electrostatic charge by moving from the material with the excess electrons to the material with the shortage of electrons. If these two unbalanced materials within the battery are connected together with a conductor, electrical current will flow as the electron moves from the negatively charged area to the positively charged area. When you use a battery, you are allowing electrons to flow from one end of the battery through a conductor and something like a light bulb to the other end of the battery. The battery will work until there is a balance of electrons at both ends of the battery.

Caution: you should never connect a conductor to the two ends of a battery without making the electrons pass through something like a light bulb which slows the flow of currents. If the electrons are allowed to flow too fast the conductor will become very hot which may cause damage to the battery.


To understand how voltage and amperage are related, it is sometimes useful to make an analogy with water. Look at the picture here of water flowing in a garden hose. Think of electricity flowing in a wire in the same way as the water flowing through the hose. The voltage causing the electrical current to flow in the wire can be considered the water pressure at the faucet, which causes the water to flow. If we were to increase the pressure at the hydrant, more water would flow in the hose. Similarly, if we increase electrical pressure or voltage, more electrons would flow in the wire.

Without EMF, there will be no current. Also, we could say that the free electrons of the atoms move in random directions unless they are pushed or pulled in one direction by an outside force, which we call electromotive force, or EMF.

Review

1. Electromotive force causes the electrons to move in a particular direction. 2. EMF is measured in units called volts. 3. Some sources of EMF are batteries, generators and photovoltaic cell.

Lesson 8 Resistance


Define resistance. Identify the unit of measurement of resistance. Discuss the similarities between resistance in a wire and the resistance in a

water hose.


Resistance is a term that describes the forces that oppose the flow of electron current in a conductor. This is measured in units called ohms. All materials naturally contain some resistance to the flow of electron current.

If we use our water analogy to help picture resistance, think of a hose that is partially plugged with sand. The sand will slow the flow of water in the hose. We can say that the plugged hose has more resistance to water flow than does an unplugged hose. The same is true with electricity. Materials with low resistance let electricity flow easily. Materials with higher resistance require more voltage (EMF) to make the electricity flow.

Is resistance good or bad?

Resistance can be both good and bad. If we are trying to transmit electricity from one place to another through a conductor, resistance is undesirable in the conductor. Resistance causes some electrical energy to get lost along the way. However, it is resistance that allows us to use electricity for heat and light. The heat that is generated from electric heaters or the light that we get from light bulbs is due to resistance. In a light bulb, the electricity flowing through the filament, or the tiny wires inside the bulb, causes them to glow white hot.

An important point to mention here is that the resistance is higher in smaller wires. Therefore, if the voltage or EMF is high, too much current will flow through small wires which will make them hot. In some cases, they could be hot enough to cause a fire or even explode. Therefore, it is sometimes useful to add components called resistors into an electrical circuit to restrict the flow of electricity and protect the components in the circuit.


Review

1. Resistance is the opposition to electrical current. 2. Resistance is measured in units called ohms. 3. Resistance is sometimes desirable and sometimes undesirable.

Fill in the blanks. Write the word or group of words that will make the sentence true

and complete.

1. A naturally occurring force that exists all around us is called _________.

2. Greek philosophers noticed that when a piece of amber was rubbed with

cloth, it would __________ pieces of straw.

3. Latin word which describes the static charge that develops when certain

materials are rubbed against amber is called ___________.

4. The natural forces that are very closely related to one another is electricity and ________.

5. Anything that has mass, weight and occupies space is called______. 6. A group of atoms bunched together is called ________. 7. A material composed of only one kind of atom is called _______. 8. A material composed of more than one kind of atom is called ________. 9. Composed of protons, neutrons, and electrons and is called ____. 10. The forces of ________ between the electrons and the protons hold an atom

together. 11. Protons have a ________ electrostatic charge.

12. Like charges repel, unlike charges _________ 13. The outer shell of the atom is called________. 14. The electron that can easily move from atom to atom is called_______. 15. The free electrons are responsible for _________. 16. A term used to describe the number of electrons moving past a fixed point in a

conductor in one second is called________. 17. The actual flow of electrons is called _______. 18. This causes the electrons to flow and is called ______. 19. The opposition to electrical current is called _________. 20. Resistance is measured in units called _________.


B. PROCESS

Lesson 1. OHMS Law The relationship of Voltage, Current, and Resistance

After reading this section you will be able to:

1. Explain the relationship of voltage, current and resistance.

2. Identify the different units of measurement and their corresponding symbols.

3. Compute for voltage, current and resistance.

The continuous movement of free electrons through the conductors of a circuit

is called a current, and it is often referred to in terms of "flow," just like the flow of a liquid through a hollow pipe.

The force motivating electrons to "flow" in a circuit is called voltage.

Free electrons tend to move through conductors with some degree of friction, or opposition to motion. This opposition to motion is properly called resistance.

The amount of current in a circuit depends on the amount of voltage available

to motivate the electrons, and also the amount of resistance in the circuit to oppose electron flow. Just like voltage, resistance is a quantity relative between two points. For this reason, the quantities of voltage and resistance are often stated as being "between" or "across" two points in a circuit.

Here are the standard units of measurement for electrical current, voltage, and resistance:

The "symbol" given for each quantity is the standard alphabetical letter used to represent that quantity in an algebraic equation. The "unit abbreviation" for each


quantity represents the alphabetical symbol used as a shorthand notation for its particular unit of measurement. And, yes, that strange-looking "horseshoe" symbol is the capital Greek letter . Each unit of measurement is named after a famous expert in electricity: The amp after the Frenchman Andre M. Ampere, the volt after the Italian Alessandro Volta, and the ohm after the German Georg Simon Ohm.

The mathematical symbol for each quantity is meaningful. "R" stands for resistance; V" is for voltage while "I" is thought to have been meant to represent "Intensity" (of electron flow), and the other symbol for voltage, "E," stands for "Electromotive force."

In this algebraic expression, voltage (E) is equal to current (I) multiplied by resistance (R). Using algebra techniques, we can manipulate this equation into two variations, solving for I and for R, respectively:

Let's see how these equations might work to help us analyze simple circuits:

In the above circuit, there is only one source of voltage (the battery, on the left) and only one source of resistance to current (the lamp, on the right). This makes it very easy to apply Ohm's Law. If we know the values of any two of the three quantities (voltage, current, and resistance) in this circuit, we can use Ohm's Law to determine the third.


In this first example, we will calculate the amount of current (I) in a circuit, given values of voltage (E) and resistance (R):

What is the amount of current (I) in this circuit?

In this second example, we will calculate the amount of resistance (R) in a circuit, given values of voltage (E) and current (I):

What is the amount of resistance (R) offered by the lamp?


In the last example, we will calculate the amount of voltage supplied by a battery, given values of current (I) and resistance (R):

What is the amount of voltage provided by the battery?

Ohm's Law is a very simple and useful tool for analyzing electric circuits. It is used so often in the study of electricity and electronics that it needs to be committed to memory by students. For those who are not yet comfortable with algebra, there's a trick to remembering how to solve for any one quantity, given the other two. First, arrange the letters E, I, and R in a triangle like this:

If you know E and I, and wish to determine R, just eliminate R from the picture and see what's left:

If you know E and R, and wish to determine I, eliminate I and see what's left:


Lastly, if you know I and R, and wish to determine E, eliminate E and see what's left:

Eventually, you'll have to be familiar with algebra to seriously study electricity and electronics, but this tip can make your first calculations a little easier to remember. If you are comfortable with algebra, all you need to do is commit E=IR to memory and derive the other two formulae from that when you need them!

REVIEW: Voltage is measured in volts, symbolized by the letters "E" or "V". Current is measured in amps, symbolized by the letter "I". Resistance measured in ohms, symbolized by the letter "R". Ohm's Law: E = IR ; I = E/R ; R = E/I

Ohms Law

Directions: Using the Ohms Law, compute for the missing value:

1.

I=2A

E=36V R=?

ACTIVITY


2.

3.

I=2A

E= R=6

I=?

E=25V R=5


Lesson 2. Complete Circuit


Explain how a circuit is formed. Identify the sources of electricity.

The electric circuit can be defined as a complete path where electricity flows from a source to the load and back again to the source.

Parts of Electric Circuit:

Source The Source is where the electricity comes from. It is sometimes called as source of emf, refers to a generator, a battery of cell or a transmission power line. It is here where the current or electricity starts to flow. The

function of the source is to establish difference from a high (+) to low (-) potential

point. The potential difference makes the current to flow.

Batteries


Power Plant

Path The Path is all the parts of the circuit where the current or electricity flows. It is the pathway of flowing electricity. The Path is made up of

conducting materials or conductor. These are materials that conduct electricity and allow electricity to pass through.

Electrical Wires


Printed Circuit Board (PCB)

Load Load are devices that consumes electricity on its operation. Examples are light bulbs, television set, electric fan, radios and many

others. They are also called current consuming devices.

Light Bulb Television


Switch The means of control allows us to control the entire circuit operation. It enables us to regulate electricity. Means of control has the capability to connect or

disconnect the flow of electricity from the source to the load. It usually comes in

different forms, maybe a slide switch, push button switch, circuits breakers and

others. The means of control functions in two ways; on or off.

Switches

When we connect various components together with wires, we create an electric circuit. The electrons must have a voltage source to create their movement and, of course, they need a path in which to travel. This path must be complete from the EMF source, through the other components and then back to the EMF source.

The voltage for any electric circuit can come from many different sources. Some common examples are batteries, power plants, fuel cells.

Power Plant

Flash Light Battery

Car Battery

Fuel Cell


When we plug an appliance into a wall outlet, voltage and current are available to us. That voltage is actually created in a power plant somewhere else and then delivered to your house by the power wires that are on poles or buried underground.

As a matter of fact, since no current can flow unless there is a voltage source, we also refer to these sources as current sources.

In addition to the voltage source, we need to have wires and other components to build an electric circuit. Remember that copper wires are conductors since they can easily conduct the flow of electrons.

We may also use resistors or other forms of loads to form a complete circuit. If we do not include resistors in our circuit, there may be too much current flowing to and from our voltage source and we could damage the voltage source.


Complete Circuit Directions: Draw a complete circuit.

Sample illustration.

Review

1. Source, Path, Load and Switch connected together form a circuit. 2. Power plants, photovoltaic cells and batteries are some examples of voltage

source

Lesson 3: Types of Circuits


1. Identify the different types of circuits. There are three types of electric circuits series, parallel and combination. Series Circuit

We've already come across series circuits. In this type of circuit, the components are arranged end to end and so the electric current flows through the


first component, then through the next component and so on, until it reaches the battery again.

Here's a series circuit to remind you.

If there's a gap in a series circuit or maybe one of the components has broken, the current can't flow and so, the whole circuit turns off. Parallel Circuit

In parallel circuits, the components don't have to be end to end because the circuit can have branches.

In a parallel circuit, the current splits as it reaches a branch so the current

flows around both branches.

If there's a gap or broken component in one of the branches of a parallel circuit, the component(s) in other branches will carry on working.


Series-Parallel Circuit Also as combination circuit, many real life circuits are combination circuits. See the sample figure used in Parallel Circuits. If we put a switch in each of the branches of a parallel circuit, we can control each component separately.

This is how our homes are wired. Review There are three types of circuit, series circuit, parallel circuit and combination circuit.

Lesson 4: Circuit Diagrams


Explain what circuit diagrams are for. Identify what the symbols in the circuit diagrams stand for.

Circuit diagrams are a visual way of showing circuits. A circuit diagram (also known as an electrical diagram, elementary diagram, or electronic schematic diagram) is a simplified conventional graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic diagram shows the components of the circuit as symbols; both types show the connections between the devices. A Block diagram is a diagram of a system, in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks (Details of block diagram will not be covered by this module).


Electricians and engineers draw circuit diagrams to help them design the actual circuits. Here is an example circuit diagram

.

The important thing to note on this diagram is what everything stands for. You see that there are straight lines that connect each of the symbols together. Those lines represent a wire.

This is the Ammeter symbol.

This is the Voltmeter symbol.

This is the resistor symbol.

This is the switch symbol.

This is the battery symbol.

The important thing to remember about this symbol is that the long bar on top represents the positive terminal on a battery while the short bar on the bottom represents the negative terminal.


Below is the actual circuit made from the circuit diagram above. Pay close attention to see how similar the diagram and how the real circuit looks.

---------

However, before you do, there are more symbols you will need to learn.

Other Electrical Symbols & Electronic Symbols

Symbol Component name Meaning/Function

Wire Symbols

Electrical Wire Conductor of electrical current


Connected Wires Connected crossing

Not Connected Wires Wires are not connected

Switch Symbols and Relay Symbols

SPST Toggle Switch Disconnects current when open

SPDT Toggle Switch

Selects between two

connections

Pushbutton Switch

(N.O)

Momentary switch - normally

open

Pushbutton Switch

(N.C)

Momentary switch - normally

closed

Ground Symbols

Earth Ground

Used for zero potential reference

and electrical shock protection.

Chassis Ground

Connected to the chassis of the

circuit

Digital / Common

Ground

Resistor Symbols

Resistor (IEEE)

Resistor reduces the current

flow.

Potentiometer (IEEE)

Adjustable resistor - has 3

terminals.

Variable Resistor /

Rheostat(IEEE)

Adjustable resistor - has 2

terminals.


Capacitor Symbols

Capacitor Capacitor is used to store

electric charge. It acts as short

circuit with AC and open circuit

with DC.

Capacitor

Polarized Capacitor Electrolytic capacitor

Polarized Capacitor Electrolytic capacitor

Variable Capacitor Adjustable capacitance

Inductor / Coil Symbols

Inductor

Coil / solenoid that generates

magnetic field

Iron Core Inductor Includes iron

Variable Inductor

Power Supply Symbols

Voltage Source Generates constant voltage

AC Voltage Source AC voltage source

Generator

Electrical voltage is generated by

mechanical rotation of the

generator

Battery Cell Generates constant voltage


Battery Generates constant voltage

Meter Symbols

Voltmeter

Measures voltage. Has very high

resistance. Connected in

parallel.

Ammeter

Measures electric current. Has

near zero resistance. Connected

serially.

Ohmmeter Measures resistance

Wattmeter Measures electric power

Lamp / Light Bulb Symbols

Lamp / light bulb

Generates light when current

flows through

Lamp / light bulb

Lamp / light bulb

Diode / LED Symbols

Diode

Diode allows current flow in one

direction only (left to right).

Zener Diode

Allows current flow in one

direction, but also can flow in the

reverse direction when above

breakdown voltage

Light Emitting Diode

(LED)

LED emits light when current

flows through


Photodiode

Photodiode allows current flow

when exposed to light

Transistor Symbols

NPN Bipolar

Transistor

Allows current flow when high

potential at base (middle)

PNP Bipolar

Transistor

Allows current flow when low

potential at base (middle)

Miscellaneous Symbols

Motor Electric motor

Transformer

Changes AC voltage from high

to low or low to high.

Electric bell Rings when activated

Buzzer Produces buzzing sound

Fuse The fuse disconnects when

current is above the threshold.

Used to protect circuit from high

currents.

Fuse

Loudspeaker

Converts electrical signal to

sound waves

Microphone

Converts sound waves to

electrical signal

Antenna Symbols

Antenna / aerial

Transmits & receives radio

waves


Antenna / aerial

Dipole Antenna Two wires simple antenna

Common Electronics Symbol

On an Oslo Paper, draw the following electronic components with their corresponding symbols and give the meaning/function of each.

NAME SCHEMATIC SYMBOL

MEANING/FUNCTION

Wire Symbols

Electrical Wire

Connected Wires

Not Connected Wires

Switch

SPST Toggle Switch

SPDT Toggle Switch

Pushbutton Switch (N.O)

Pushbutton Switch (N.C.)

Ground Symbols

Earth Ground

Chassis Ground

Digital Common

Resistors

Fixed Resistor

Variable Resistor

Capacitors

Capacitor (Fixed)

Polarized Capacitor

Variable Capacitor

Inductor/Coils

Inductor

Iron Core Inductor

Variable Inductor


Power Supply

Voltage Source

AC Voltage Source

Battery Cell

Battery

Meter

Voltmeter

Ammeter

Ohmmeter

Lamp/Lights

Lamp/Light Bulb

Diodes

Diode

Zener Diode

Light Emitting Diode

Photodiode

Transistors

NPN

PNP

Miscellaneous

Fuse

Buzzer

Loudspeaker

Microphone

Lesson 5: Resistor


1. Define resistor. 2. Identify types of resistor.

Resistors ( R ), are the most fundamental and commonly used of all the electronic components. There are many different types of resistors available, from very small surface mount chip resistors up to large wirewound power resistors. The principal job of a resistor within an electrical or electronic circuit is to "resist" or to impede the flow of electrons.


A Typical Fixed Type Resistor

Resistors are "Passive Devices", that is, they contain no source of power or amplification but only attenuate or reduce the voltage signal passing through them. This attenuation results in electrical energy being lost in the form of heat as the resistor resists the flow of electrons through it.

Most resistors produce a voltage drop across themselves when electrical current flows through them because of Ohm's Law and different values of resistance produce different values of current or voltage. Resistance is the opposition to the flow of current. This can be very useful in electronic circuits by controlling or reducing either the current flow or voltage produced across them.

In all Electrical and Electronic circuit diagrams and schematics, the most commonly used symbol for a fixed value resistor is that of a "zig-zag" type line with the value of its resistance given in Ohms, . Resistors have fixed resistance values from less than one ohm, ( 10M ) in value. Fixed resistors have only one single value of resistance, for example 100'sbut variable resistors (potentiometers) can provide an infinite number of resistance values between zero and their maximum value.

Standard Fixed Type Resistor Symbols

The symbol used in schematic and electrical drawings for a Resistor can either be a "zig-zag" type line or a rectangular box.

All modern fixed value resistors can be classified into four broad groups;

Carbon Composition Resistor - Made of carbon dust or graphite paste, low wattage values

Film or Cermet Resistor - Made from conductive metal oxide paste, very low wattage values

Wire-wound Resistor - Metallic bodies for heatsink mounting, very high wattage ratings

Composition Type Resistors

Carbon Resistors are the most common type of Composition Resistors. Carbon resistors are a cheap general purpose resistor used in electrical and electronic circuits. Their resistive element is manufactured from a mixture of finely ground carbon dust or graphite (similar to pencil lead) and a non-conducting ceramic (clay) powder to bind it all together.


Carbon Resistor

The Carbon Composite Resistor is a low to medium type power resistor. Power rating is from 0.25 or 1/4 of a Watt up to 5 Watts.

Carbon composite resistors are very cheap to make and are therefore commonly used in electrical circuits. However, due to their manufacturing process carbon type resistors have very large tolerances so for more precision and high value resistances, film type resistors are used instead.

Film Type Resistors

The generic term "Film Resistor" consist of Metal Film, Carbon Film and Metal Oxide Film resistor types, which are generally made by depositing pure metals, such as nickel, or an oxide film, such as tin-oxide, onto an insulating ceramic rod or substrate.

Film Resistor

Film type resistors also achieve a much higher maximum ohmic value compared to other types and values in excess of 10M (10 Million s) are available.


Metal Film Resistors have much better temperature stability than their carbon equivalents, lower noise and are generally better for high frequency or radio frequency applications. Metal Oxide Resistors have better high surge current capability with a much higher temperature rating than the equivalent metal film resistors.

Metal Film Resistors are prefixed with a "MFR" notation (eg MFR100k) and a CF for Carbon Film types. Metal film resistors power rating is 0.05 (1/20th) of a Watt up to 1/2 Watt. Generally speaking Film resistors are precision low power components.

Wirewound Type Resistors

Another type of resistor, called a Wirewound Resistor, is made by winding a thin metal alloy wire (Nichrome) or similar wire onto an insulating ceramic former in the form of a spiral helix similar to the film resistor above. These types of resistors are generally only available in very low ohmic high precision values (from 0.01 to 100k) due to the gauge of the wire and number of turns possible on the former making them ideal for use in measuring circuits and Whetstone bridge type applications.

They are also able to handle much higher electrical currents than other resistors of the same ohmic value with power ratings in excess of 300 Watts. These high power resistors are moulded or pressed into an aluminum heat sink body with fins attached to increase their overall surface area to promote heat loss and cooling. These types of resistors are called "Chassis Mounted Resistors". They are designed to be physically mounted onto heatsinks or metal plates to further dissipate the generated heat increasing their current carrying capabilities even further.


Wirewound Resistor

Wirewound resistor types are prefixed with a "WH" or "W" notation (eg WH10) and are available in the WH aluminium cladded package with power ratings from 1W to 300W or more.

Variable Resistor

Variable resistors or potentiometers are used in many areas of electronics. They are used for volume and gain controls as well as a variety of other applications. Preset variable resistors or potentiometers are also used in circuits that need a small adjustment to be made to set the circuit up after manufacture.


For convenience variable resistors are made by having a fixed resistor with a variable tapping point. As a result of this arrangement these devices are often called potentiometers or "pots" for short. Here the potentiometer consisted of a length of resistance wire with a tapping point that could be moved along the wire - the same configuration as that used in these variable resistors.

As shown in the diagram below, a variable resistor consists of a track which provides the resistance path. Two terminals of the device are connected to both the ends of the track. The third terminal is connected to a wiper that decides the motion of the track. The motion of the wiper through the track helps in increasing and decreasing the resistance.

The track is usually made of a mixture of ceramic and metal or can be made of carbon as well. As a resistive material is needed, carbon film type variable resistors are mostly used. They find applications in radio receiver circuits, audio amplifier circuits and TV receivers. A track made in a straight path is called a slider. As the position of a slider cannot be seen or confirmed according to the adjustment of resistance, a stopping mechanism is usually included to prevent the hazards caused due to over rotation.

There are two major types:

1. Rotary: The most common form of variable resistor or potentiometer is a rotary version. This version of potentiometer uses a rotary motion to move the slider around a track that compromises most of a circle, with contacts at either end of the track in the area where part of the circle is missing. This form is widely used with knobs on a spindle for the actual control, and they are found in many applications from providing adjustments on test equipment through to being used for volume controls on domestic radios.


2. Slider: Slider controls are those variable resistors that slide in a linear fashion, i.e. in a straight line. These controls take up more front panel space, but are much easier to use under some circumstances. For example they are widely used for audio mixers and lighting desks. The advantage of sliders is that it is easier to control them quite precisely and compare the relative positions of a number of sliders. It is also possible to control a number of sliders together.

Review

1. A Resistor is an electronic component used to resist the flow of electrons. 2. There are many types of resistors, for fixed type; Carbon Composition, Film or Cermet, and Wirewound. The variable types are rotary and slider.


Lesson 6: Other Electronic Components After reading this section you will be able to do the following: 1. Identify other electronic components and explain their basic function. Capacitor

A device that consists essentially of two conducting surfaces separated by a dielectric material like air, paper, mica, ceramic, glass, or Mylar. It makes it possible to store electric energy. Electrons are detained within a capacitor. This, in effect, is stored electricity. The component is designed intentionally to have a definite amount of capacitance. This capacitance is a property that exists whenever insulating material permits the storage of electricity. It is measured in Farad (F) micro Farad (F), nano Farad (nF), and picoFarad (pF). Characteristics of Capacitor: 1. It can store electric charge even though the voltage source is already disconnected. 2.It can discharge electrical voltages.

Fixed type capacitor

Electrolytic Tantalum Mica


Symbols of Capacitor

Diode

A diode is a two-terminal electronic component with asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other. It is a semiconductor device.

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, these diodes are forms of rectifiers.

Transistor

A semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit.


Integrated Circuit (IC)

An integrated circuit, or IC, is small chip that can function as an amplifier, oscillator, timer, microprocessor, or even computer memory. An IC is a small wafer, usually made of silicon, that can hold anywhere from hundreds to millions of transistors, resistors, and capacitors. These extremely small electronics can perform calculations and store data.

Review

Capacitor is an electronic component used to charge and discharge electric energy. Diode is an electronic component used to allow the current to pass in one direction only. Transistor is used mainly for switching amplification purposes. Integrated Circuits or ICs can function as an amplifier, oscillator, timer, microprocessor or memory; and can hold hundreds to millions of transistors, resistors and capacitors.


LESSON 7. BASIC HAND TOOLS & EQUIPMENT

After reading this section you will be able to:

1. Identify some basic tools and equipment and explain their uses.

2. Value the proper maintenance of hand tools and equipment.

Sic t

Assembling an electronic project and making it work is a good start in helping one to learn troubleshooting methods as well as becoming familiar with your tools, test equipments, electronic schematics and component color codes.

It's hard to produce a good project/product or service unless proper electronic tools and knowledge of using them and observing safety precautions are adequate. Some of the basic tools & equipment that should prove useful are listed below.

Electric Drill and Drill Bits

Electric drill and drill bits in the range of 1/8 inch to 1/2 inch will come in handy when you need to drill holes on the printed circuit board (PCB) that has been etched. Drilling of plastic or metal enclosure that houses the printed circuit board are sometimes necessary.


Electric Drill

A suitable PCB Mini Hand Drill can be easily obtained from any electronic shop.

Soldering Iron

In large and heavy metal work, welding is used in joining metals permanently. In electronics work, soldering is used to join pigtails of components, transistor leads, and IC pins among others. Soldering is the process of heating materials, and joints to be soldered and applying solder on the heated joints to ensure permanent connection.


Soldering Iron A 30 Watt to 40 Watt soldering iron with tips of 1/8 inch to 1/2 inch can be

used for soldering of through hole components. Soldering of surface mount components may require smaller tips depending on the sizes of the components. Soldering iron normally will last a long time if it is taken care of properly by keeping the tips clean and well tinned.

Basic Soldering Guide


What Is Soldering?

Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal (solder) into the joint, the filler metal having a lower melting point than the workpiece. Soldering differs from welding in that soldering does not involve melting the work pieces. In soldering, the filler metal melts at a higher temperature, but the workpiece metal does not melt. Formerly nearly all solders contained lead, but environmental concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.


Solder is a thin tube, usually rolled in spools, made of various metal alloys. Its job is to hold the individual components together. The individual components and their quantities can vary, but for computer electronics, youre usually looking at a 60% tin and 40% lead. Lead-free solder is also available, though it has higher melting temperatures and less wettability, meaning you may need a better soldering iron to use it and removing it can be more tedious.

It is better to use lead free solder because it functions well and is environmentally friendly.

A solders tube is filled with flux, a substance that gets rid of oxidation and helps clean the surfaces involved in the fusing process. For electronic use, we want rosin-core/rosin-flux solder. Acid-flux is used in plumbing and the acid can damage the sensitive components on PCBs.


Wire Stripper

Wire stripper is used to strip off wire insulator from its conductor before it is used to connect to another wire or soldered into the printed circuit board. Some wire stripper or wire cutter has a measurement engraved on it to indicate the length that can be stripped.

Long nose Pliers

A pair of 4-inch long nose pliers will come in handy when you need to hold components that have short leads that need to be soldered onto the PCB but will be too hot to handle with bare hands. It will also be useful to hold the component that needs to be de-soldered from the board.


Side-Cutting Pliers

A pair of 4-inch side cutting pliers will come in handy when one needs to trim off excess component leads on the printed circuit board. It can also be used to cut wires into shorter length before being used. Tweezers

Small tweezers are used to hold much smaller components especially when doing soldering and de-soldering of surface mount components.


Allen Wrench set

Allen wrench set is sometimes used to unscrew or screw Allen type of screws. Philips Screwdrivers

Various sizes of Philips head screwdrivers will be handy as a lot of electronics projects that use screws are Philips Head type.


Flat Head Screwdrivers

Flat head screwdrivers of various sizes are also necessary as many screws commonly used are of this type.

Hammer

A small, light hammer will be useful when assembling projects that involve casing.


Socket wrench sets

A socket wrench set includes nut drivers, hex drivers, and starters in assorted sizes that will come in handy during the assembly work of electronics project.


Blade Cutter

A Blade Cutter will be useful when one need to cut PCB, wires or remove some copper from the printed circuit board.

Equipment

Aside from hand tools, certain equipment are also needed for more accurate and quality output. Three of the commonly used equipment are presented here for you to be familiar with their uses and the proper way of maintaining them.

a. Oscilloscope. An oscilloscope (commonly abbreviated CRO, for

cathode ray oscilloscope, or simply scope) is a piece of electronic test

equipment that allows signal voltage to be viewed.


b. Signal generator. A device which produces simple waveforms.

Such devices contain an electronic oscillator, a circuit that is

capable of creating a repetitive waveform. These are typically used in

simple electronics repair and design where they are used to stimulate a

circuit under test

.

Oscilloscope and signal generator should be given regular

check-up for at least once a week by connecting them in the power

line. This will prevent their components from having moisture that might

cause trouble in their circuits.

c. Volt-OHM-Milliammeter (VOM). A handheld device that combines

three functions: as a voltmeter that measures both ac and dc voltages:

an ohmmeter that measures resistance: and milliammeter that

measures small amount of dc current. It is called Multitester (Multi-

tester) or Multimeter (Multi-tester). It can measure to a very high

degree of accuracy. They can be used to troubleshoot electrical

problems in a wide array of industrial and household devices such

as electronic equipment, motor controls, domestic appliances, power

supplies, and wiring systems. As safety precautions in the maintenance

of this instrument, the following should be observed:


General Rule for Analog:

Always rest the function switch at 250Vac

if an off position is not available in the

instrument.

For current and voltage measurement,

always set the function switch in the

correct setting which is a little higher than

the expected current or voltage present in

the circuit.

Optimise the range for the best reading. If possible adjust it so that

the maximum deflection of the meter can be gained. In this way the

most accurate reading will be gained.

When making measurements, Keep your fingers behind the finger

guards on the test probes.

Place the instrument in a cool dry place, away from any magnetic

devices, and free from vibrations.


Hand Tools Classification There are four different types of hand tools according to their uses:

Cutting Tools:These are used to cut a physical object into pieces. For example: side cutting pliers and blade cutters.

Gripping Tools: These tools are used for gripping objects by using leverage.

For example: long nose pliers and twizzers. Striking Tools: The striking tools are the most widely used tools. Chiseling,

punching and riveting can be done properly using striking tools. Hand-held striking tools have been used in a variety of disciplines as leverage devices providing a striking force to complete endless variety of tasks. For example: hammers & chisels

Driving Tools: These are designed in such a way that insertion, tightening,

loosening, removing screws, bolts, nails or other pointed objects or hard-to-turn items are done by applying torque. For example: screwdrivers, nut drivers and wrenches.

Struck or Hammered Tools: These tools are used for forcing a bolt, pin, or

rivet in or out of a hole. For example: punches, nail sets, chisels .

Maintenance Tips of Electronic Tools

Good quality tools can last a lifetime if they are taken care of properly. Ensure that the tools are used only for their intended purposes, keep them lubricated with a light film of oil to inhibit rust, keep the tools clean and sharp, keep the soldering tips clean and well tinned and ensure that proper use of the tools are always adhered to by following the instructions in the proper use of tools.

Common Faults in Using Hand Tools

Pliers:

Do not increase the handle length of the

pliers to more leverage. Use a larger pair of

pliers or bolt cutters if necessary.

Do not substitute pliers for a wrench when

turning bolts and nuts. Pliers cannot grip

these items properly and might cause a slip and cause an accident.


Never use pliers as a hammer on the handle. Such abuse is likely

to result in cracks or breaks.

Cut hardened wire only with pliers designed for that purpose.

Always cut the wire in right angle. Never rock from side to side or

bend wire back and forth against the cutting edges.

Screwdrivers:

Never use screw drivers as a pry bar, chisel, and punch stirrer or

scraper.

Never use screwdrivers with broken or worn-out handles.

Screwdrivers of these kinds should have tags to indicate that it is

defective.

Never use pliers on a screwdriver for extra leverage. Only use

wrench or screwdrivers specially designed for the purpose.

Utility Knives/ Blades:

Do not use dull blades because they require more force, thus, they

are more likely to slip. Replace the blades when they start to tear

instead of cut.

Never leave a knife unattended with the blade exposed.

Dont bend or apply side loads to blades by using them to open

cans or loosen tight cover of containers. Blades are brittle and can

snap easily.


Inventory of Tools

1. Take hold of the tools found in your shop/house and acquaint yourself with their parts. Try to identify the name and the use of each while being extra careful not to damage the tools nor hurt yourself.

2. Categorize some available tools in your shop according to:

Cutting Tools Gripping

Tools Striking Tools Driving Tools

Additional Activities: The teacher may bring his/her class to an electronic shop and let the students

observe how the skilled electronic technician uses different kinds of tools. View a video about how skilled electronic technician uses different kind of

tools. (The teacher may show this video entitled Collins Lab:Electronic Tools at http://www.youtube.com/watch?v=Kv7Y8nAOoFE ).

Review: 1. Some basic hand tools with the corresponding uses are: Electric drill is used to drill holes on PCB; Soldering iron is used to join metals and solder electronic components on PCB; Wire stripper is used to strip off wire insulators; Long nose pliers are used to hold small components; Side cutting pliers are used to cut wires and trim off excess component leads; and Screwdrivers are used to drive or remove screw. Some measuring equipments with their uses are: Oscilloscope allows signal voltage to be viewed; Signal generator produces simple waveforms; and Multitester (VOM) can measure voltage, resistance and small amount of current. Tools can be categorized to Cutting, Gripping, Striking and Driving. 2. Well maintained tools and equipment are important so that they are readily available and function properly


IDENTIFICATION. Identify the following tools/equipment based on the cited uses. 1. Used to join metals and solder components. 2. Used to strip insulators. 3. Used to hold small components. 4. Used to drill holes on PCB. 5. Used to cut wires. 6. Used to drive screw. 7. Used to cut unnecessary copper on PCB. 8. Used to measure voltage, resistance and current. 9. Produces simple waveforms. 10. Used to view signal. ESSAY. Write the importance of well maintained tools and equipment. Sample Scoring Criteria

Beginning

(1)

Developing

(2)

Approaching

Proficiency

(3)

Proficient

(5)

Organization No idea or

unclear flow of

ideas.

Some signs of

and/or abrupt

change of

ideas.

Some ideas

and sequence

may be

improved.

Sequence and

transition of

ideas was

effective.

Details Inappropriate

/off-topic

Too general. Contained

some

appropriate

details or

examples.

Convincingly

interpreted.

Sample Rating Scale:

Points earned Equivalent Percentage

10 100

9 97


8 93

7 90

6 86

5 83

4 79

3 76

2 72

1 69

0 65

C. REFLECT AND UNDERSTAND

Lesson1/Activity1: Resistor Color Coding

We learned in the previous lesson that there are many different types of Resistors available and that they can be used in electronic circuits to control the flow of current or voltage in many different ways. But in order to do this, the actual resistor needs to have some form of "resistive" or "resistance" value. Resistors are available in a range of different resistance values from fractions of an Ohm ( ) to millions of Ohms.

Obviously, it would be impractical to have available resistors of every possible value for example, 1,2, 3, 4 etc, because literally hundreds of thousands, if not millions of different resistors would need to exist to cover all the possible values. Instead, resistors are manufactured in what are called "preferred values" with their resistance value printed onto their body in colored ink.

4 Colored Bands


The resistance value, tolerance, and wattage rating are generally printed onto the body of the resistor as numbers or letters when the resistors body is big enough to read the print, such as large power resistors. But when the resistor is small such as a 1/4W carbon or film type, these specifications must be shown in some other manner as the print would be too small to read.

So to overcome this, small resistors use colored painted bands to indicate both their value with the physical size of the resistor indicating its wattage rating. These colored painted bands produce a system of identification generally known as Resistors Color Code.

A resistors color code markings are always read one band at a time starting from the left to the right, with the larger width tolerance band oriented to the right side indicating its tolerance. By matching the color of the first band with its associated number in the digit column of the color chart below the first digit is identified and this represents the first digit of the resistance value. Again, by matching the color of the second band with its associated number in the digit column of the color chart we get the second digit of the resistance value and so on as illustrated below:


The Standard Resistor Color Code Chart.


The Resistor Color Code Table (Four Bands).

Color Digit

(Leftmost band for

first significant

digit)

Digit

(Stands for

second significant

digit)

Multiplier

(Represents the multiplier or number of

zeros after the two digits)

Tolerance

Black 0 0 1

Brown 1 1 10

(0) 1%

Red 2 2 100

(00) 2%

Orange 3 3 1,000

(000)

Yellow 4 4 10,000 (0000)

Green 5 5 100,000

(00000) 0.5%

Blue 6 6 1,000,000

(000000) 0.25%


Violet 7 7 10,000,000

(0000000) 0.1%

Grey 8 8

White 9 9

Gold

0.1

(Decimal point is after the first

significant digit)

5%

Silver

0.01

(Decimal point is before the

first significant digit)

10%

None 20%

Calculating Resistor Values

It is important to understand the Resistor Color Code system and understand how to apply it in order to get the correct value of the resistor. The "left-hand" or the most significant colored band is the band which is nearest to a connecting lead with the color coded bands being read from left-to-right as follows;

Digit, Digit, Multiplier = Color, Color x 10 color in Ohm's ('s)

For example, a resistor has the following colored markings;

Yellow Violet Red = 4 7 2 = 4 7 x 102 = 4700 or 4k7.

The fourth and fifth bands are used to determine the percentage tolerance of the resistor. Resistor tolerance is a measure of the resistors variation from the specified resistive value and is a consequence of the manufacturing process and is expressed as a percentage of its "nominal" or preferred value.

Most of the four band resistors have tolerances of 5%, 10% and 20%. The color code used to denote the tolerance rating of a resistor is given as;

Brown = 1%, Red = 2%, Gold = 5%, Silver = 10 %


If resistor has no fourth tolerance band then the default tolerance would be at 20%.

Examples:

1. The value of a resistor is 10 Ohms with a tolerance of 5%. Let us find out from the 4 Bands Resistor Color Chart what would be the color bands of the resistor.

black black

brown gold

1 0 - 5 %

Reading: 10 ohms

The colors that you have located in the table should match the digit and

multiplier in the first example. Continue checking with other examples.

2. The value of the resistor is 100 ohms with a tolerance of 10%.

black brown

brown silver

1 0 0 10 %

Reading: 100 ohms

3. In this example, the value of the resistor is 2000 0hms. Three zeroes

Represent a thousand which can be substitute for abbreviation with

Letter K. Thus the value of the resistor will appear as 2 K ohms.

black red

red

2 0 00


Reading: 2,000 ohms or 2K

4. In example 4, the third color band is gold, multiply the first two digits by 0.1. Therefore, the resistance would be 4.7 ohms.

violet gold

yellow

4 7 0.1

Reading: 4.7 ohms

5. In example 5, the third color is silver so the decimal multiplier is .01.The decimal point is placed before the first digit. The reading will be .22

ohms.

red silver

red

2 2 .01

Reading: .22 ohms

It is sometimes easier to remember the resistor color code by using mnemonics or phrases that have a separate word in the phrase to represent each of the Ten + Two colors in the code. However, these sayings are often very crude but never the less effective for remembering the resistor colors. Here are just a few of the more "cleaner" versions but many more exist:

Black Brown Red Orange Yellow Green Blue Violet Gray

Bad Boys Ring Our Young Girls But Vicky Goes Without Bad Boys Ring Our Young Girls But Vicky Gives Willingly-- Get Some Now (This one is only slightly better because it includes the tolerance bands of Gold, Silver, and None).


Additional Information: Some resistors, particularly metal film types, are marked with a number or letter code to indicate the value and tolerance instead of the color code. 3K3J Value: 3,300 ohms + 5% or 3.3K, + 5% The letter K represents both the multiplier and the location of the decimal point in the number of the resistor.

Multipliers Value Represented

R 1

K 1000

M 1000000

The tolerance is given by the last letter.

Tolerance Value Represented

F 1 %

G 2 %

J 5 %

K 10 %

M 20 %

Assessment 1: Resistor Color Coding

Multiple Choice: Choose the letter of the best answer (Ask the students to show their computation).

1. What is the value of a resistor with a Blue-Black-Orange-Gold Color Code?

A. 600 Ohms 5% B. 6K Ohms5% C.60K Ohms5% D. 600K Ohms 5%

2. What is the value of a resistor with a Red-Violet-Brown-Silver Color Code?

A. 27 Ohms10% B. 270 Ohms10% C. 2.7K Ohms10% D. 27K Ohms10%


3. What is the value of a resistor with a Yellow-Yellow-Yellow-Gold Color Code?

A. 440 Ohms5% B. 4.4K Ohms5% C. 44K Ohms5% D. 440K Ohms5%

4. What is the value of a resistor with a Green-Blue-Black-Silver Color Code?

A. 56 Ohms10% B. 560 Ohms10% C. 5.6K Ohms10% D. 56K Ohms10%

5. What is the color of representing 20% tolerance?

A. Black B. Silver C. Gold D. No Color

Additional Activity/Assessment:

Resistor Tabulation

Materials: 10 pieces - Carbon resistors, 1 watt, assorted values 1 pc - Resistor Tabulation form Procedures: 1. Arrange the resistors on a piece of styrofor. 2. Identify the colors of the resistors one by one and record them in the resistor tabulation form. 3. Compute for the resistance value of each resistor by following the color coding scheme. 4. Write the value of the resistance in the tabulation form.


Sample Resistor Tabulation Form (Photocopy this or simply copy on your notebook)

# 1st COLOR BAND

2nd COLOR BAND

3RD COLOR BAND

TOLERANCE COMPUTED VALUE

1

2

3

4

5

6

7

8

9

10

Performance Test

Learners Name: Date:

Competency: Test Attempt

1st 2nd 3rd

Directions: CALL THE TEACHER and ask him / her to assess your performance in the following critical task using the performance

OVERALL EVALUATION

LEVEL ACHIEVED

PERFORMANCE LEVEL


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

4 - Can perform this skill without supervision and with initiative and adaptability to problem situations.

3 - Can perform this skill satisfactorily without 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.

The teacher will affix his/her initial on the level achieved.

PERFORMANCE STANDARDS

For acceptable achievement, all items should receive a "Yes" response.

Yes No N/A

1. Can recite the colors of the color coding chart in order without looking at the chart.

2. Can identify the first color of the carbon resistor.

3. Can interpret equivalent numerical value of each color in the chart

4. Can calculate the color coded value of the resistor.

5. Can give the over-all value of the resistor after calculation.

Lesson 2/Activity 2: Proper Use of Soldering Iron

Many whove never used a soldering iron are afraid

of damaging the equipment, but more important is the

danger to yourself! Soldering irons get really hot. Be sure

to wear safety glasses, keep loose clothing and hair out of

the way, and be careful with your fingers. Better still, use

protective gloves. Solder can contain lead, so be sure to

wash your hands thoroughly after handling it. It is also really

important to work in a well-ventilated area because the

fumes from the rosin can cause damage to your lungs when

inhaled.


A. Cleaning and Tinning the Tip

In order to conduct heat properly, your soldering iron needs to be free of any old solder. After being exposed to air, it oxidizes and thus insulates against heat. We want heat to conduct so that we can apply everything quickly and efficiently. A dirty tip means that youll have to hold the iron on longer and risk heat damage to the component or PCB. Keep a wet sponge handy, and after the soldering iron is fully heated, softly scrape it against the sponge to remove old solder. The tip should be clean and shiny, or at least very close to it.

Tinning protects the tip and allows heat to conduct better via the presence of new solder. On the hot iron, carefully apply a small amount of fresh solder and coat the tip. It should still be shiny if youve done it right. As soon as you tin the tip, start soldering your components together. After a few joints, clean and re-tin again before putting your iron away into storage. This will really help increase the longevity of your tool.


Joining Parts on PCB

ia- electronics lm grade 7 & 8 p&d

Documents

process lesson

soldering components

electronic components

consumer electronic

basic competencies

low voltage

transfer performance

complete circuit