chapter 1

• Electricity


  A form of energy generated by friction, induction or chemical change, having magnetic, chemical and radiant effect
• Electrons in motion


  The definition of electricity
• Electricity has been around since the existence of the universe, discovered accidentally by the ancient Greeks sometime in 600 B.C.
• Elelectricity

  • Consists of electrons, protons and neutrons
• Electron


  The negatively charged particle of an atom, the negative charge of electricity
• Proton


  The positively charged particle of an atom, the positive charge of electricity
• Neutron


  The particle of an atom which is not electrically charged
• Ampere


  The standard unit used in measuring the strength of an electric current, named after Andre M. Ampere
• When there is too much flow of electricity in a small conductor or wire

  Heat is produced which eventually may blow-off the protective device called a fuse, or burn the wire insulator and create fire
• Watt


  The rate or measure of power used or consumed
• Circuit


  The wire installations that supply current to light and convenient outlets
• Resistance


  The friction or opposition to the flow of current by the wires and transformers, analogous to plumbing installation, where the flow of water is subjected to resistance caused by friction between the water and the inside wall of the pipe, and the various forms of turns and fittings
• Resistance (DC)


  The term used for friction
• Impedance (AC)


  The term used for friction
• Factors that influence conductor resistance

  • Composition of the conductor
  • Length of wire
  • Cross sectional area of wire
  • Temperature
• Composition of the conductor


  • Conductor having free electrons that has low resistance
• Length of wire


  • The longer the wire, the higher the resistance
• Cross sectional area of wire


  • The bigger the cross sectional area of wire, the lower its resistance
• Temperature


  • Metal offers high resistance to high temperature (heat)
• Direct Current (DC)


  Electricity that flows in one direction
• Flow of DC electricity

  From negative to positive
• Source of DC electricity

  Dry cell or storage battery
• Alternating Current (AC)


  Electricity that constantly reverses its direction of flow
• AC electricity is universally accepted because of its unlimited number of applications
• Transformer


  • Simple static device
  • Magnetic core
  • Primary and secondary windings