What you are expected to learn

At the end of this module, you should be able to:

• Define atom, matter, element, and molecule.

• List the parts of an atom.

• Identify the unit for measuring current.

• Draw the symbol used to represent current flow in a circuit.

• Describe the difference between conductors, insulators, and semiconductors.

• Define difference of potential, electromotive force, and voltage.

• Draw the symbol used to represent voltage.

• Identify the unit used to measure voltage.

• Define resistance.

• Identify characteristics of resistance in a circuit.

• Identify the unit for measuring resistance.

• Draw the symbol used to represent resistance in a circuit.

IT IS IMPORTANT TO UNDERSTAND SOME SIMPLE, GENERAL PHYSICS PRINCIPLES IN ORDER TO HAVE A full grasp of electricity and electronics. It is not necessary to know high-level mathematics. In science, you can talk about qualitative things or quantitative things, the “what” versus the “how much.” For now, we are concerned only about the “what.” The “how much” will come later.

We see applications of electricity all around us, especially in the electronic products we own and operate every day. For example, we depend on electricity for lighting, heating, air conditioning and for the operation of our vehicles, cell phones, appliances, computers, and home entertainment systems to name a few. The applications of electricity are extensive and almost limitless to the imagination.

Although there are many applications of electricity, electricity itself can be explained in terms of electric charge, voltage, and current. In this module, you will be introduced to the basic concepts of electricity which include a discussion of the following topics: basic atomic structure, the coulomb unit of electric charge, the volt unit of potential difference, the ampere unit of current, and the ohm unit of resistance.

How to learn from this module

Going through this module can be both a fun and a meaningful learning experience. All you need to do is make use of your time and resources efficiently. To do this, here are some

tips for you:

1. Take time in reading and understanding each lesson. It is better to be slow but sure than to hurry finishing the module only to find out that you missed the concepts you are supposed to learn.

2. Do not jump from one chapter to another. Usually, the lessons are arranged such that one is built upon another, hence an understanding of the first is essential in comprehending the succeeding lessons.

3. Be honest. When answering the test items, do not turn to the key to correction page unless you are done. Likewise, when performing experiments, record only what you have really observed.

4. Safety first. Perform the experiments with extra precaution. Wear safety gears whenever necessary.

5. Don’t hesitate to ask. If you need to clarify something, approach your teacher or any knowledgeable person.

What to do before (Pretest)

Electricity is present in all matter in the form of electrons and protons.

Everything, whether natural or man-made, can be broken down into either an element or a compound.

However, the smallest part of each of these is the atom.

The atom is made up of protons, neutrons, and electrons. The protons and neutrons group together to form the center of the atom called the nucleus. The electrons orbit the nucleus in shells located at various distances from the nucleus.

The electron is the basic particle of negative charge, and the proton is the basic particle of positive charge.

When appropriate external force is applied to electrons in the outermost shell, they are knocked loose and become free electrons. The movement of free electrons is called current. The external force needed to create this current is called voltage.

As it travels along its path, the current encounters some opposition, called resistance.

Lesson 1: MATTER, ELEMENTS AND COMPOUNDS

• Matter is anything that occupies space.

• Matter can be an element or compound.

• An element is the basic building block of nature.

• A compound is a chemical combination of two or more elements.

• A molecule is the smallest unit of a compound that retains the properties of the compound.

Lesson 1.1: A CLOSER LOOK AT ATOM

• An atom is the smallest unit of matter that retains the structure of the element.

• An atom consists of a nucleus, which contains protons and neutrons. It also has one or more electrons that orbit around the nucleus.

• Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.

• Charges of opposite polarity attract, and charges of like polarity repel.

• The atomic number of an element is the number of protons in the nucleus, balanced by an equal number of orbital electrons.

• The atomic weight of an atom is the sum of protons and neutrons.

• The orbits of the electrons are called shells.

• The outer shell of an atom is called the valence shell.

• The number of electrons in the valence shell is called the valence.

• Electron valence refers to the number of electrons in the outermost shell of an atom. Except for H and He, the goal of valence is eight for all atoms.

• An atom that has the same number of protons as electrons is electrically balanced.

• The process by which atoms gain or lose electrons is called ionization.

• Conductors are materials with low resistance.

• A conductor is a material in which electrons can move easily from one atom to the next.

• Insulators are materials with high resistance.

• An insulator is a material in which electrons tend to stay in their own orbit. Another name for insulator is dielectric.

Conductor VS Insulator Simulation Activity

Sort Conductors and Insulator Activity

Lesson 2: The Four Basic Electrical Concept

Simple Circuit Simulation Activity

Lesson 2.1: CURRENT

•The flow of electrons is called current.

• Current is represented by the symbol I.

• The charge of 6,240,000,000,000,000,000 (or 6.24 10^18) electrons is called a coulomb.

• An ampere of current is measured when one coulomb of charge moves past a given point in one second.

• Ampere is represented by the symbol A.

• Current is measured in amperes.

• An electric current flows through a conductor when there is an excess of electrons at one end and a deficiency at the other end.

Lesson 2.2:VOLTAGE

• A source that supplies excess electrons represents a potential or electromotive force.

• The potential or electromotive force is referred to as voltage.

• Voltage is the force that moves electrons in a circuit.

• The symbol E is used to represent voltage.

• A volt (V) is the unit for measuring voltage.

Lesson 2.3:RESISTANCE

• Resistance is the opposition to current flow.

• Resistance is represented by the symbol R.

• All materials offer some resistance to current flow.

• The resistance of a material is dependent on the material’s size, shape, and temperature.

• Conductors are materials with low resistance.

• Insulators are materials with high resistance.

• Resistance is measured in ohms.

• The Greek letter omega (Ω) is used to represent ohms.

• Conductance is the reciprocal of resistance. The symbol for conductance is G , and the basic unit of measure is the siemens (S).

• R . 1/G and G . 1/R.

Lesson 2.4:POWER

• Power is the rate at which energy is delivered to a circuit.

• Power is also the rate at which energy (heat) is dissipated by the resistance in a circuit.

• Power is measured in watts.

• Power is the product of current and voltage: P = I x E

• The total power dissipated in a series or parallel circuit is equal to the sum of the power dissipated by the individual components.

PT = P1 + P2 + P3 . . . Pn

Important Terms

• Alternating current (ac) a current that periodically reverses in direction as the alternating voltage periodically reverses in polarity.

• Ampere the basic unit of current.

• Atom the smallest particle of an element that still has the same characteristics as the element.

• Atomic number the number of protons, balanced by an equal number of electrons, in an atom.

• Circuit a path for current fl ow.

• Compound a combination of two or more elements.

• Conductance the reciprocal of resistance.

• Conductor any material that allows the free movement of electric charges, such as electrons, to provide an electric current.

• Conventional current the direction of current fl ow associated with positive charges in motion. The current fl ow direction is from a positive to a negative potential, which is in the opposite direction of electron fl ow.

• Coulomb the basic unit of electric charge. 1 C 6.25x 10^ 18 electrons or protons.

• Current a movement of electric charges around a closed path or circuit.

• Dielectric another name for insulator.

• Direct current (dc) a current fl ow that has just one direction.

• Electron the most basic particle of negative charge.

• Electron fl ow the movement of electrons that provides current in a circuit. The current fl ow direction is from a negative to a positive potential, which is in the opposite direction of conventional current.

• Electron valence the number of electrons in an incomplete outermost shell of an atom.

• Element a substance that cannot be decomposed any further by chemical action.

• Free electron an electron that can move freely from one atom to the next.

• Insulator a material with atoms in which the electrons tend to stay in their own orbits.

• Ion an atom that has either gained or lost one or more valence electrons to become electrically charged.

• Molecule the smallest unit of a compound with the same chemical characteristics.

• Neutron a particle contained in the nucleus of an atom that is electrically neutral.

• Nucleus the massive, stable part of the atom that contains both protons and neutrons.

• Ohm the unit of resistance.

• Potential difference a property associated with two unlike charges in close proximity to each other.

• Proton the most basic particle of positive charge.

• Resistance the opposition to the flow of current in an electric circuit.

• Semiconductor a material that is neither a good conductor nor a good insulator.

• Siemens the unit of conductance.

• Static electricity any charge, positive or negative, that is stationary or not in motion.

• Volt the unit of potential difference or voltage.

Self Check

Additional Information