Thursday, September 3, 2009

LEARN BASIC ELECTRICAL

ELECTRICAL MEANINGS
  • # Electrical is energy
  • # Electricity is the movement of electrons in the conductor
  • # Electricity is available in two forms, namely cash flow and continue alternating current
  • # Electricity supplied to house is of 220-240V in the form of alternating current (AC / AU).
RESOURCE ELECTRICAl

i. Cleaning Batery ii. Wet Batery iii. Bicycle dynamo

Method to produce electricity:

1. In the process of chemical reactions - examples Tues and cell dry wet 2. In response induction ordering - a bicycle dynamo and generator example 3. Others such as:
  • 1. solar power
  • 2. action of heat

Tues Cleaning

1. Tues dry produce voltage 1.5 volts
2. Two cells connected in series dry will produce 3.0 volts Two cells connected series of dry
3. Electric current generated by the current dry Tues directly (AT / DC)
4. Electricity produced by dry Tues is the result of chemical reactions
5. Tues dry electric tools used in portable low-power - such as lighting picit, alarm clock, games tools

Tues Cleaning Division


Cause = A positive, B = Former zinc, electrolyte C = D = Batang carbon, E = cause negative

Tues Wet

1. Tues wet usually produces voltage 6.0-volt, 12 volt and 24 volt
2. Tues wet can be recharged with a battery charger device
3. Tues better known as wet batteries
4. Tues wet used in vehicles such as motorcycles, cars, trucks and buses

Division Tues wet


A = Plate positive (lead peroxide), B = positive terminal, C = Penyelang, D = Plate negative (lead), E = electrolyte (sulfuric acid Melt)

Bicycle dynamo

1. Bicycle dynamo produces voltage 6 volts - 12 volts
2. Electric current generated by a dynamo is alternating current (AU / AC)
3. Electricity generated by a dynamo is a result of the induction ordering

Dinamo Bicycle Division


Player A =, B = permanent magnets, iron core C = D = coil wire, E = electric source

Type-cell types

1. Tues alkali
2. Tues mercury
3. Tues lithium
4. Tues nickel cadmium

ELECTRICITY USE

i. Grinders ii. Light Pendafluor iii. TV iv. Sterika v. Radio

1. To produce:
1.

light
* Example - pendafluor lights, incandescent lights, LED
2.

Logo
* Example - radio, siren, buzzer, bell
3.

heat
* Example - Hair Dryer, bakers, iron, kettle, oven
4.

movement
* Example - Fan, grinders, electric motors
5.

electronic signal
* Example - calculator, game pad, computer

Electrical wire

1. Copper wire beranemal
1. Coils used to make electricity
2.

Single core
1. Used in the field of electronic
2. Able electrical power drain is very low
3.

Twin-core
1. Used for low-power electrical appliances such as lighting and sound box
2. To make a connection to the source of negative and positive wires or live and neutral wires only
4.

Three core cable
1. Used to connect high-power electric tools
2. To create a live connection to the source, neutral and earth


I = beranemal copper wire, single core wire = II, III = twin core wire, IV = three core cable

Battery Type

1. 2 pin plugs
1. Used to connect the electricity supply to low-power electric tools
2. Radio, TV, shaver
2. 3-pin plugs
1. There are 2 types, 3 pin plug 13 ampere and 15 ampere 3-pin plug
2. Used to connect the electricity supply to electrical equipment high
3. Rice cooker, oven, refrigerator, iron using 3-pin plug 13 ampere
4. Air Conditioning with 3-pin plug 15 ampere


I = 2 pin plug, II = 3-pin plug


i. Position tamatan L, N, and E
ii. Installing the correct color code
iii. Three core cable blue, green and brown

3 pin wiring plug 13 ampere

1. Tools


Pen Test = I, II = Penjalur wire, folding knives III =
2. Materials
1. 3 core cable
3. Steps

1. Remove cable insulation approximately 4 cm
2. Jalurkan end of the three wires
3. Pintalkan three wire end
4. Open the charger cover
5. Tamatan install the core wire which according to the code correctly, ie
* Wireless brown / black ---> tamatan life (L)
* Wire blue / red -----> tamatan neutral (N)
* Wire green / green-yellow earth Tamatan ------> (E)
6. Close the plug and install screws

Fuse


i. Symbols fuse ii. Fuse cartridge iii. Fuse wire

1. Used to determine circuit or short circuit in the event of surplus electricity
2. Provide protection to electrical equipment from damage and burns
3. Unit of measurement is the ampere fuse
4. There are two types of fuse
1. Cartridge fuse - used in 3-pin plug and fuse services home
1.

13A fuse
* Used in 3-pin plug 13 ampere
2.

30A fuse
* Used in the fuse service in domestic electrical supply system
2. Wire fuse - used in the distribution box in the house berfius
5. Rates commonly used fuse is 5A, 10A, 13A and 30A
6. Fuse made of tin or lead alloy

Incandescent LAMP AND LAMP PENDAFLUOR


i. Incandescent lamp

1. Kelalang
2. Filament
3. Pin
4. Electrical source

ii. Light Pendaflour

1. Holder
2. Tube
3. Host
4. Starter switch

Incandescent lamp

1. Characteristics of incandescent lamps
1. Produce light yellow eyes menyilaukan
2. Light heat
3. Leaving a black shadow
4. Using the power of many
2. Division incandescent lamps
1. = Filament burn and produce light
2. = Argon gas to prevent the filament burns and broken
3. Sesuntuh = connecting filament to cause electrical
4. = Protecting glass bulb and filament argon gas

Fluorescent lamps

1.

Advantages Lamp pendaflour
1. Bright white color and not menyilaukan points
2. Cold light
3. Save electricity
4. Not leaving a black shadow
2.

Lighting Division pendarflour
1. = Fluorescent tubes containing mercury and argon gas, producing ultraviolet light
2. = Tube holder to hold the pin electrode
3. Cok = supply voltage high
4. Switches turn on lights Kick =
5. Host = site holds the parts of other light








MAKSUD ELEKTRIK

  • Elektrik ialah tenaga
  • Elektrik ialah pergerakan elektron dalam pengalir
  • Elektrik boleh didapati dalam dua bentuk arus iaitu arus terus dan arus ulang alik
  • Elektrik yang dibekalkan kerumah-rumah adalah sebanyak 220-240V dalam bentuk arus ulang alik (AC/AU).
  • Di Malaysia elektrik dibekalkan oleh TNB (Tenaga Nasional Berhad).

    SUMBER ELEKTRIK


    i. Sel Kering ii. Sel Basah iii. Dinamo Basikal

    Kaedah menghasilkan elektrik:

    1. Melalui proses tindak balas kimia - contoh sel kering dan sel basah
    2. Melalui tindak balas aruhan kemagnetan - contoh dinamo basikal dan janakuasa
    3. Lain-lain seperti:
      1. kuasa solar
      2. tindakan haba

    Sel Kering

    1. Sel kering menghasilkan voltan 1.5 volt
    2. Dua sel kering yang disambungkan secara siri akan menghasilkan 3.0 volt


      Dua sel kering disambung siri

    3. Arus elektrik yang dihasilkan oleh sel kering ialah arus terus (AT/DC)
    4. Tenaga elektrik yang dihasilkan oleh sel kering adalah daripada hasil tindak balas kimia
    5. Sel kering digunakan pada alatan elektrik mudah alih berkuasa rendah - seperti lampu picit, jam loceng, alatan permainan

    Bahagian Sel kering


    A = Punca positif , B = Bekas zink , C = elektrolit , D = Batang karbon , E = Punca negatif

    Sel Basah

    1. Sel basah biasanya menghasilkan voltan 6.0 volt, 12 Volt dan 24 volt
    2. Sel basah boleh dicas semula dengan alat pengecas bateri
    3. Sel basah lebih dikenali sebagai bateri
    4. Sel basah digunakan di dalam kenderaan seperti motor, kereta, lori dan bas

    Bahagian sel basah


    A = Plat positif (plumbum peroksida) , B= Terminal positif , C = Penyelang , D = Plat negatif (plumbum) , E = Elektrolit (Asid Sulfurik Cair)

    Dinamo Basikal

    1. Dinamo basikal menghasilkan voltan 6 volt - 12 volt
    2. Arus elektrik yang dihasilkan oleh dinamo ialah arus ulang alik (AU/AC)
    3. Tenaga elektrik yang dihasilkan oleh dinamo ialah hasil daripada aruhan kemagnetan

    Bahagian Dinamo Basikal


    A = Pemutar , B = Magnet kekal , C = Teras besi, D = gegelung dawai , E = punca elektrik

    Jenis-jenis sel

    1. Sel Alkali
    2. Sel merkuri
    3. Sel lithium
    4. Sel nikel kadmium

    KEGUNAAN ELEKTRIK

    i. Pengisar ii. Lampu Pendafluor iii. TV iv. Sterika v. Radio

    1. Untuk menghasilkan :

      1. cahaya

        • Contoh - lampu pendafluor, lampu pijar, LED

      2. bunyi

        • Contoh - Radio, siren, buzzer, loceng

      3. haba

        • Contoh - Pengering rambut, pembakar roti, seterika, cerek, ketuhar

      4. gerakan

        • Contoh - Kipas angin, pengisar, motor elektrik

      5. isyarat elektronik

        • Contoh - kalkulator, pad permainan, komputer

    WAYAR ELEKTRIK

    1. Wayar kuprum beranemal
      1. Digunakan untuk membuat gegelung elektrik

    2. Teras tunggal

      1. Digunakan dalam bidang elektronik
      2. Mampu mengalirkan elektrik kuasa sangat rendah

    3. Teras kembar

      1. Digunakan untuk alat elektrik kuasa rendah seperti lampu dan peti suara
      2. Untuk membuat sambungan ke punca negatif dan positif atau wayar hidup dan wayar neutral sahaja

    4. Kabel teras tiga

      1. Digunakan untuk menyambung alatan elektrik berkuasa tinggi
      2. Untuk membuat sambungan ke punca hidup, neutral dan bumi


      5. I = Wayar kuprum beranemal , II = Wayar teras tunggal , III = Wayar teras kembar , IV = Kabel teras tiga

    JENIS PLAG

    1. Plag 2 pin
      1. Digunakan untuk menyambung bekalan elektrik kepada alatan elektrik berkuasa rendah
      2. Radio , TV, Pencukur
    2. Plag 3 pin
      1. Terdapat 2 jenis, plag 3 pin 13 ampere dan plag 3 pin 15 ampere
      2. Digunakan untuk menyambung bekalan elektrik kepada alatan elektrik berkuasa tinggi
      3. Periuk nasi, ketuhar, peti sejuk, seterika mengunakan plag 3 pin 13 ampere
      4. Pendingin hawa menggunakan plag 3 pin 15 ampere


      3. I = plag 2 pin , II = plag 3 pin


    i. Kedudukan tamatan L, N, dan E
    ii. Pemasangan kod warna yang betul
    iii. Kabel teras tiga biru, hijau dan coklat

    PENDAWAIAN PLAG 3 PIN 13 AMPERE

    1. Alatan


      I = Pena Ujian , II = Penjalur wayar , III = Pisau lipat

    2. Bahan
      1. Kabel teras 3
    3. Langkah-langkah

      1. Buangkan penebat kabel kira-kira 4 cm
      2. Jalurkan hujung ketiga-tiga wayar
      3. Pintalkan ketiga-tiga hujung wayar
      4. Buka penutup plag
      5. Pasangkan teras pada tamatan mengikut kod wayar yang betul iaitu
        • Wayar coklat/hitam ---> tamatan hidup(L)
        • Wayar biru/merah -----> tamatan neutral (N)
        • Wayar hijau/hijau-kuning ------>Tamatan bumi (E)
      6. Tutup semula plag dan pasangkan skru

    FIUS


    i. Simbol fius ii. Fius katrij iii. Fius dawai

    1. Digunakan untuk memutuskan litar sekiranya berlaku litar pintas atau lebihan tenaga elektrik
    2. Memberi perlindungan kepada alatan elektrik daripada rosak dan terbakar
    3. Unit ukuran fius ialah ampere
    4. Terdapat dua jenis fius
      1. Fius katrij - digunakan dalam plag 3 pin dan fius perkhidmatan rumah

        1. Fius 13A

          • Digunakan dalam plag 3 pin 13 ampere

        2. Fius 30A

          • Digunakan dalam fius perkhidmatan dalam sistem bekalan elektrik domestik
      2. Fius Dawai - digunakan dalam kotak agihan berfius dalam rumah
    5. Kadar fius yang biasa digunakan ialah 5A, 10A, 13A dan 30A
    6. Fius dibuat daripada aloi timah atau plumbum

    LAMPU PIJAR DAN LAMPU PENDAFLUOR


    i. Lampu pijar
    1. Kelalang
    2. Filamen
    3. Pin
    4. Sumber elektrik
    		ii. Lampu Pendaflour
    1. Pemegang
    2. Tiub
    3. Perumah
    4. Suis penghidup

    Lampu pijar

    1. Ciri-ciri lampu pijar
      1. Menghasilkan cahaya kuning yang menyilaukan mata
      2. Cahayanya panas
      3. Meninggalkan bayang hitam
      4. Menggunakan kuasa elektrik yang banyak
    2. Bahagian lampu pijar
      1. Filamen = menyala dan mengeluarkan cahaya
      2. Gas argon = mencegah filamen daripada terbakar dan putus
      3. Sesuntuh = menyambung filamen ke punca elektrik
      4. Mentol kaca = melindungi gas argon dan filamen

    Lampu pendarfluor

    1. Kelebihan Lampu pendaflour

      1. Warnanya putih terang dan tidak menyilaukan mata
      2. Cahayanya sejuk
      3. Menjimatkan elektrik
      4. Tidak meninggalkan bayang hitam

    2. Bahagian Lampu pendarflour

      1. Tiub pendarfluor = berisi gas argon dan merkuri, menghasilkan cahaya ultra ungu
      2. Pemegang tiub = memegang pin elektrod
      3. Cok = membekalkan voltan tinggi
      4. Suis Penghidup = menghidupkan lampu
      5. Perumah = tapak memegang bahagian-bahagian lampu yang lain
    www.comfori.com/new/EG027.pdf -
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    NOTA KEMAHIRAN HIDUP TINGKATAN SATU

    Elektrik

    MAKSUD ELEKTRIK

  • Elektrik ialah tenaga
  • Elektrik ialah pergerakan elektron dalam pengalir
  • Elektrik boleh didapati dalam dua bentuk arus iaitu arus terus dan arus ulang alik
  • Elektrik yang dibekalkan kerumah-rumah adalah sebanyak 220-240V dalam bentuk arus ulang alik (AC/AU).
  • Di Malaysia elektrik dibekalkan oleh TNB (Tenaga Nasional Berhad).

    SUMBER ELEKTRIK


    i. Sel Kering ii. Sel Basah iii. Dinamo Basikal

    Kaedah menghasilkan elektrik:

    1. Melalui proses tindak balas kimia - contoh sel kering dan sel basah
    2. Melalui tindak balas aruhan kemagnetan - contoh dinamo basikal dan janakuasa
    3. Lain-lain seperti:
      1. kuasa solar
      2. tindakan haba

    Sel Kering

    1. Sel kering menghasilkan voltan 1.5 volt
    2. Dua sel kering yang disambungkan secara siri akan menghasilkan 3.0 volt


      Dua sel kering disambung siri

    3. Arus elektrik yang dihasilkan oleh sel kering ialah arus terus (AT/DC)
    4. Tenaga elektrik yang dihasilkan oleh sel kering adalah daripada hasil tindak balas kimia
    5. Sel kering digunakan pada alatan elektrik mudah alih berkuasa rendah - seperti lampu picit, jam loceng, alatan permainan

    Bahagian Sel kering


    A = Punca positif , B = Bekas zink , C = elektrolit , D = Batang karbon , E = Punca negatif

    Sel Basah

    1. Sel basah biasanya menghasilkan voltan 6.0 volt, 12 Volt dan 24 volt
    2. Sel basah boleh dicas semula dengan alat pengecas bateri
    3. Sel basah lebih dikenali sebagai bateri
    4. Sel basah digunakan di dalam kenderaan seperti motor, kereta, lori dan bas

    Bahagian sel basah


    A = Plat positif (plumbum peroksida) , B= Terminal positif , C = Penyelang , D = Plat negatif (plumbum) , E = Elektrolit (Asid Sulfurik Cair)

    Dinamo Basikal

    1. Dinamo basikal menghasilkan voltan 6 volt - 12 volt
    2. Arus elektrik yang dihasilkan oleh dinamo ialah arus ulang alik (AU/AC)
    3. Tenaga elektrik yang dihasilkan oleh dinamo ialah hasil daripada aruhan kemagnetan

    Bahagian Dinamo Basikal


    A = Pemutar , B = Magnet kekal , C = Teras besi, D = gegelung dawai , E = punca elektrik

    Jenis-jenis sel

    1. Sel Alkali
    2. Sel merkuri
    3. Sel lithium
    4. Sel nikel kadmium

    KEGUNAAN ELEKTRIK

    i. Pengisar ii. Lampu Pendafluor iii. TV iv. Sterika v. Radio

    1. Untuk menghasilkan :

      1. cahaya

        • Contoh - lampu pendafluor, lampu pijar, LED

      2. bunyi

        • Contoh - Radio, siren, buzzer, loceng

      3. haba

        • Contoh - Pengering rambut, pembakar roti, seterika, cerek, ketuhar

      4. gerakan

        • Contoh - Kipas angin, pengisar, motor elektrik

      5. isyarat elektronik

        • Contoh - kalkulator, pad permainan, komputer

    WAYAR ELEKTRIK

    1. Wayar kuprum beranemal
      1. Digunakan untuk membuat gegelung elektrik

    2. Teras tunggal

      1. Digunakan dalam bidang elektronik
      2. Mampu mengalirkan elektrik kuasa sangat rendah

    3. Teras kembar

      1. Digunakan untuk alat elektrik kuasa rendah seperti lampu dan peti suara
      2. Untuk membuat sambungan ke punca negatif dan positif atau wayar hidup dan wayar neutral sahaja

    4. Kabel teras tiga

      1. Digunakan untuk menyambung alatan elektrik berkuasa tinggi
      2. Untuk membuat sambungan ke punca hidup, neutral dan bumi


      5. I = Wayar kuprum beranemal , II = Wayar teras tunggal , III = Wayar teras kembar , IV = Kabel teras tiga

    JENIS PLAG

    1. Plag 2 pin
      1. Digunakan untuk menyambung bekalan elektrik kepada alatan elektrik berkuasa rendah
      2. Radio , TV, Pencukur
    2. Plag 3 pin
      1. Terdapat 2 jenis, plag 3 pin 13 ampere dan plag 3 pin 15 ampere
      2. Digunakan untuk menyambung bekalan elektrik kepada alatan elektrik berkuasa tinggi
      3. Periuk nasi, ketuhar, peti sejuk, seterika mengunakan plag 3 pin 13 ampere
      4. Pendingin hawa menggunakan plag 3 pin 15 ampere


      3. I = plag 2 pin , II = plag 3 pin


    i. Kedudukan tamatan L, N, dan E
    ii. Pemasangan kod warna yang betul
    iii. Kabel teras tiga biru, hijau dan coklat

    PENDAWAIAN PLAG 3 PIN 13 AMPERE

    1. Alatan


      I = Pena Ujian , II = Penjalur wayar , III = Pisau lipat

    2. Bahan
      1. Kabel teras 3
    3. Langkah-langkah

      1. Buangkan penebat kabel kira-kira 4 cm
      2. Jalurkan hujung ketiga-tiga wayar
      3. Pintalkan ketiga-tiga hujung wayar
      4. Buka penutup plag
      5. Pasangkan teras pada tamatan mengikut kod wayar yang betul iaitu
        • Wayar coklat/hitam ---> tamatan hidup(L)
        • Wayar biru/merah -----> tamatan neutral (N)
        • Wayar hijau/hijau-kuning ------>Tamatan bumi (E)
      6. Tutup semula plag dan pasangkan skru

    FIUS


    i. Simbol fius ii. Fius katrij iii. Fius dawai

    1. Digunakan untuk memutuskan litar sekiranya berlaku litar pintas atau lebihan tenaga elektrik
    2. Memberi perlindungan kepada alatan elektrik daripada rosak dan terbakar
    3. Unit ukuran fius ialah ampere
    4. Terdapat dua jenis fius
      1. Fius katrij - digunakan dalam plag 3 pin dan fius perkhidmatan rumah

        1. Fius 13A

          • Digunakan dalam plag 3 pin 13 ampere

        2. Fius 30A

          • Digunakan dalam fius perkhidmatan dalam sistem bekalan elektrik domestik
      2. Fius Dawai - digunakan dalam kotak agihan berfius dalam rumah
    5. Kadar fius yang biasa digunakan ialah 5A, 10A, 13A dan 30A
    6. Fius dibuat daripada aloi timah atau plumbum

    LAMPU PIJAR DAN LAMPU PENDAFLUOR


    i. Lampu pijar
    1. Kelalang
    2. Filamen
    3. Pin
    4. Sumber elektrik
    		ii. Lampu Pendaflour
    1. Pemegang
    2. Tiub
    3. Perumah
    4. Suis penghidup

    Lampu pijar

    1. Ciri-ciri lampu pijar
      1. Menghasilkan cahaya kuning yang menyilaukan mata
      2. Cahayanya panas
      3. Meninggalkan bayang hitam
      4. Menggunakan kuasa elektrik yang banyak
    2. Bahagian lampu pijar
      1. Filamen = menyala dan mengeluarkan cahaya
      2. Gas argon = mencegah filamen daripada terbakar dan putus
      3. Sesuntuh = menyambung filamen ke punca elektrik
      4. Mentol kaca = melindungi gas argon dan filamen

    Lampu pendarfluor

    1. Kelebihan Lampu pendaflour

      1. Warnanya putih terang dan tidak menyilaukan mata
      2. Cahayanya sejuk
      3. Menjimatkan elektrik
      4. Tidak meninggalkan bayang hitam

    2. Bahagian Lampu pendarflour

      1. Tiub pendarfluor = berisi gas argon dan merkuri, menghasilkan cahaya ultra ungu
      2. Pemegang tiub = memegang pin elektrod
      3. Cok = membekalkan voltan tinggi
      4. Suis Penghidup = menghidupkan lampu
      5. Perumah = tapak memegang bahagian-bahagian lampu yang lain

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    Wednesday, September 2, 2009

    Basic Electricity

    ELECTRICITY - A Secondary Energy Source

    A Secondary Source
    The Science of Electricity
    How Electricity is Generated/Made
    The Transformer - Moving Electricity
    Measuring Electricity

    energy calculator
    links page
    recent statistics

    A SECONDARY SOURCE

    Electricity is the flow of electrical power or charge. It is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources. The energy sources we use to make electricity can be renewable or non-renewable, but electricity itself is neither renewable or non-renewable.

    Electricity is a basic part of nature and it is one of our most widely used forms of energy. Many cities and towns were built alongside waterfalls (a primary source of mechanical energy) that turned water wheels to perform work. Before electricity generation began over 100 years ago, houses were lit with kerosene lamps, food was cooled in iceboxes, and rooms were warmed by wood-burning or coal-burning stoves. Beginning with Benjamin Franklin's experiment with a kite one stormy night in Philadelphia, the principles of electricity gradually became understood. Thomas Edison helped change everyone's life -- he perfected his invention -- the electric light bulb. Prior to 1879, direct current (DC) electricity had been used in arc lights for outdoor lighting. In the late-1800s, Nikola Tesla pioneered the generation, transmission, and use of alternating current (AC) electricity, which can be transmitted over much greater distances than direct current. Tesla's inventions used electricity to bring indoor lighting to our homes and to power industrial machines.

    Despite its great importance in our daily lives, most of us rarely stop to think what life would be like without electricity. Yet like air and water, we tend to take electricity for granted. Everyday, we use electricity to do many jobs for us -- from lighting and heating/cooling our homes, to powering our televisions and computers. Electricity is a controllable and convenient form of energy used in the applications of heat, light and power.

    THE SCIENCE OF ELECTRICITY developed by the National Energy Education Development Project

    In order to understand how electric charge moves from one atom to another, we need to know something about atoms. Everything in the universe is made of atoms—every star, every tree, every animal. The human body is made of atoms. Air and water are, too. Atoms are the building blocks of the universe. Atoms are so small that millions of them would fit on the head of a pin.

    Atoms are made of even smaller particles. The center of an atom is called the nucleus. It is made of particles called protons and neutrons. The protons and neutrons are very small, but electrons are much, much smaller. Electrons spin around the nucleus in shells a great distance from the nucleus. If the nucleus were the size of a tennis ball, the atom would be the size of the Empire State Building. Atoms are mostly empty space.

    If you could see an atom, it would look a little like a tiny center of balls surrounded by giant invisible bubbles (or shells). The electrons would be on the surface of the bubbles, constantly spinning and moving to stay as far away from each other as possible. Electrons are held in their shells by an electrical force.

    The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. An electrical charge is a force within the particle. Protons have a positive charge (+) and electrons have a negative charge (-). The positive charge of the protons is equal to the negative charge of the electrons. Opposite charges attract each other. When an atom is in balance, it has an equal number of protons and electrons. The neutrons carry no charge and their number can vary.

    The number of protons in an atom determines the kind of atom, or element, it is. An element is a substance in which all of the atoms are identical (the Periodic Table shows all the known elements). Every atom of hydrogen, for example, has one proton and one electron, with no neutrons. Every atom of carbon has six protons, six electrons, and six neutrons. The number of protons determines which element it is.

    Electrons usually remain a constant distance from the nucleus in precise shells. The shell closest to the nucleus can hold two electrons. The next shell can hold up to eight. The outer shells cans hold even more. Some atoms with many protons can have as many as seven shells with electrons in them.

    The electrons in the shells closest to the nucleus have a strong force of attraction to the protons. Sometimes, the electrons in the outermost shells do not. These electrons can be pushed out of their orbits. Applying a force can make them move from one atom to another. These moving electrons are electricity.

    STATIC ELECTRICITY

    Electricity has been moving in the world forever. Lightning is a form of electricity. It is electrons moving from one cloud to another or jumping from a cloud to the ground. Have you ever felt a shock when you touched an object after walking across a carpet? A stream of electrons jumped to you from that object. This is called static electricity.

    Have you ever made your hair stand straight up by rubbing a balloon on it? If so, you rubbed some electrons off the balloon. The electrons moved into your hair from the balloon. They tried to get far away from each other by moving to the ends of your hair.

    They pushed against each other and made your hair move—they repelled each other. Just as opposite charges attract each other, like charges repel each other.

    MAGNETS AND ELECTRICITY

    The spinning of the electrons around the nucleus of an atom creates a tiny magnetic field. Most objects are not magnetic because the atoms are arranged so that the electrons spin in different, random directions, and cancel out each other.

    Magnets are different; the molecules in magnets are arranged so that the electrons spin in the same direction. This arrangement of atoms creates two poles in a magnet, a North-seeking pole and a South-seeking pole.


    Bar Magnet

    A magnet is labeled with North (N) and South (S) poles. The magnetic force in a magnet flows from the North pole to the South pole. This creates a magnetic field around a magnet.

    Have you ever held two magnets close to each other? They don’t act like most objects. If you try to push the South poles together, they repel each other. Two North poles also repel each other.

    Turn one magnet around and the North (N) and the South (S) poles are attracted to each other. The magnets come together with a strong force. Just like protons and electrons, opposites attract.

    These special properties of magnets can be used to make electricity. Moving magnetic fields can pull and push electrons. Some metals, like copper have electrons that are loosely held. They can be pushed from their shells by moving magnets. Magnets and wire are used together in electric generators.

    BATTERIES PRODUCE ELECTRICITY

    A battery produces electricity using two different metals in a chemical solution. A chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other. One end of the battery is attached to one of the metals; the other end is attached to the other metal. The end that frees more electrons develops a positive charge and the other end develops a negative charge. If a wire is attached from one end of the battery to the other, electrons flow through the wire to balance the electrical charge. A load is a device that does work or performs a job. If a load––such as a lightbulb––is placed along the wire, the electricity can do work as it flows through the wire. In the picture above, electrons flow from the negative end of the battery through the wire to the lightbulb. The electricity flows through the wire in the lightbulb and back to the battery.

    ELECTRICITY TRAVELS IN CIRCUITS

    Electricity travels in closed loops, or circuits (from the word circle). It must have a complete path before the electrons can move. If a circuit is open, the electrons cannot flow. When we flip on a light switch, we close a circuit. The electricity flows from the electric wire through the light and back into the wire. When we flip the switch off, we open the circuit. No electricity flows to the light. When we turn a light switch on, electricity flows through a tiny wire in the bulb. The wire gets very hot. It makes the gas in the bulb glow. When the bulb burns out, the tiny wire has broken. The path through the bulb is gone. When we turn on the TV, electricity flows through wires inside the set, producing pictures and sound. Sometimes electricity runs motors—in washers or mixers. Electricity does a lot of work for us. We use it many times each day.

    HOW ELECTRICITY IS GENERATED

    A generator is a device that converts mechanical energy into electrical energy. The process is based on the relationship between magnetism and electricity. In 1831, Faraday discovered that when a magnet is moved inside a coil of wire, electrical current flows in the wire.

    A typical generator at a power plant uses an electromagnet—a magnet produced by electricity—not a traditional magnet. The generator has a series of insulated coils of wire that form a stationary cylinder. This cylinder surrounds a rotary electromagnetic shaft. When the electromagnetic shaft rotates, it induces a small electric current in each section of the wire coil. Each section of the wire becomes a small, separate electric conductor. The small currents of individual sections are added together to form one large current. This current is the electric power that is transmitted from the power company to the consumer.

    An electric utility power station uses either a turbine, engine, water wheel, or other similar machine to drive an electric generator or a device that converts mechanical or chemical energy to generate electricity. Steam turbines, internal-combustion engines, gas combustion turbines, water turbines, and wind turbines are the most common methods to generate electricity. Most power plants are about 35 percent efficient. That means that for every 100 units of energy that go into a plant, only 35 units are converted to usable electrical energy.

    Most of the electricity in the United States is produced in steam turbines. A turbine converts the kinetic energy of a moving fluid (liquid or gas) to mechanical energy. Steam turbines have a series of blades mounted on a shaft against which steam is forced, thus rotating the shaft connected to the generator. In a fossil-fueled steam turbine, the fuel is burned in a furnace to heat water in a boiler to produce steam. Coal, petroleum (oil), and natural gas are burned in large furnaces to heat water to make steam that in turn pushes on the blades of a turbine.

    Did you know that most electricity generated in the United State comes from burning coal? In 2007, nearly half (48.5%) of the country's 4.1 trillion kilowatthours of electricity used coal as its source of energy.

    Natural gas, in addition to being burned to heat water for steam, can also be burned to produce hot combustion gases that pass directly through a turbine, spinning the blades of the turbine to generate electricity. Gas turbines are commonly used when electricity utility usage is in high demand. In 2007, 21.6% of the nation's electricity was fueled by natural gas.

    Petroleum can also be used to make steam to turn a turbine. Residual fuel oil, a product refined from crude oil, is often the petroleum product used in electric plants that use petroleum to make steam. Petroleum was used to generate about two percent (2%) of all electricity generated in U.S. electricity plants in 2007.

    Nuclear power is a method in which steam is produced by heating water through a process called nuclear fission. In a nuclear power plant, a reactor contains a core of nuclear fuel, primarily enriched uranium. When atoms of uranium fuel are hit by neutrons they fission (split), releasing heat and more neutrons. Under controlled conditions, these other neutrons can strike more uranium atoms, splitting more atoms, and so on. Thereby, continuous fission can take place, forming a chain reaction releasing heat. The heat is used to turn water into steam, that, in turn, spins a turbine that generates electricity. Nuclear power was used to generate 19.4% of all the country's electricity in 2007.

    Hydropower, the source for 5.8% of U.S. electricity generation in 2007, is a process in which flowing water is used to spin a turbine connected to a generator. There are two basic types of hydroelectric systems that produce electricity. In the first system, flowing water accumulates in reservoirs created by the use of dams. The water falls through a pipe called a penstock and applies pressure against the turbine blades to drive the generator to produce electricity. In the second system, called run-of-river, the force of the river current (rather than falling water) applies pressure to the turbine blades to produce electricity.

    Geothermal power comes from heat energy buried beneath the surface of the earth. In some areas of the country, enough heat rises close to the surface of the earth to heat underground water into steam, which can be tapped for use at steam-turbine plants. This energy source generated less than 1% of the electricity in the country in 2007.

    Solar power is derived from the energy of the sun. However, the sun's energy is not available full-time and it is widely scattered. The processes used to produce electricity using the sun's energy have historically been more expensive than using conventional fossil fuels. Photovoltaic conversion generates electric power directly from the light of the sun in a photovoltaic (solar) cell. Solar-thermal electric generators use the radiant energy from the sun to produce steam to drive turbines. In 2007, less than 1% of the nation's electricity was based on solar power.

    Wind power is derived from the conversion of the energy contained in wind into electricity. Wind power, less than 1% of the nation's electricity in 2007, is a rapidly growing source of electricity. A wind turbine is similar to a typical wind mill.

    Biomass includes wood, municipal solid waste (garbage), and agricultural waste, such as corn cobs and wheat straw. These are some other energy sources for producing electricity. These sources replace fossil fuels in the boiler. The combustion of wood and waste creates steam that is typically used in conventional steam-electric plants. Biomass accounts for about 1% of the electricity generated in the United States.

    THE TRANSFORMER - MOVING ELECTRICITY

    To solve the problem of sending electricity over long distances, William Stanley developed a device called a transformer. The transformer allowed electricity to be efficiently transmitted over long distances. This made it possible to supply electricity to homes and businesses located far from the electric generating plant.

    The electricity produced by a generator travels along cables to a transformer, which changes electricity from low voltage to high voltage. Electricity can be moved long distances more efficiently using high voltage. Transmission lines are used to carry the electricity to a substation. Substations have transformers that change the high voltage electricity into lower voltage electricity. From the substation, distribution lines carry the electricity to homes, offices and factories, which require low voltage electricity.

    MEASURING ELECTRICITY

    Electricity is measured in units of power called watts. It was named to honor James Watt, the inventor of the steam engine. One watt is a very small amount of power. It would require nearly 750 watts to equal one horsepower. A kilowatt represents 1,000 watts. A kilowatthour (kWh) is equal to the energy of 1,000 watts working for one hour. The amount of electricity a power plant generates or a customer uses over a period of time is measured in kilowatthours (kWh). Kilowatthours are determined by multiplying the number of kW's required by the number of hours of use. For example, if you use a 40-watt light bulb 5 hours a day, you have used 200 watthours, or 0.2 kilowatthours, of electrical energy. See our Energy Calculator section to learn more about converting units.


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