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Alternating Current
—Electric current that reverses the direction of its flow many times a second.
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Ampere
—The unit of electric current. One ampere is a rate of flow of change equal to one coulomb per second (I=QIT)
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Batteries
—Charge chemical energy into electricity.
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Conductor
—A substance that transmits electricity.
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Direct Current
—Current that flows in only one direction.
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Electric Circuit
—It is the path or paths followed by an electric current.
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Electric Current
—It’s a flow of electrons or ions.
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Electric Field
—It is the space around a charged particle in which its charge has an effect.
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Electrical Induction
—The process by which an electrically charged object charges another object without touching it.
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Electrical Resistance
—The resistance provided by the structure of a conductor to the flow of electric charges.
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Electricity
—Electric current used as a source of power.
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Electromotive Force
—This is a voltage. It is the pressure that pushes electric current through a circuit.
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Electron
—A particle of an atom that carries one unit of negative charge.
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Energy
—The capacity for doing work.
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Fuse
—Prevents too much current from flowing through a circuit.
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Generator
—Converts mechanical energy into electricity.
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Hydroelectric Power
—Power that is produced from the conversion of the kinetic energy of water.
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Ion
—Its an atom that has either gained or lost electrons and is electrically charged.
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Kilowatt Hour
—A unit of energy equal to a power of one kilowatt (1000w) acting for one hour.
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Ohms Law
—Current is equal to electromotive force (e.m.f.) divided by resistance.
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Proton
—One of the fundamental particles located in the nuclei of atoms; each proton has a positive charge equal in amount to that of the negatively charged electron.
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Resistance
—Is the opposition to the flow of an electric current in a circuit.
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Static Electricity
—Is electrons or ions that are not moving.
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Terminal
—A device to which an electrical connection is made. Also, the point at which current enters and leaves an electric circuit.
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Transformer
—A device that increases or decreases the voltage of
alternating current.
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QUIZ
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1. What is the purpose of the electrical path of a circuit?
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2. What is an electric current?
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3. What is energy?
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4. Under what conditions will a lamp light?
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5. Which of the three elementary particles listed below are the most important in electricity?
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____
The proton, electron or neutron. Explain your answer.
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6. Name the three kinds of particles that make up an atom.
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7. Describe Benjamin Franklin’s electrical experiment.
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8. Name some metals that are conductors of electricity.
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9. Name the three basic requirements for every useful electrical system.
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10. List the three basic parts of an electrical circuit and describe their functions.
(figure available in print form)
Figure 1. Elementary particles and the atom.
The positive charges in the nucleus, of course, belongs to the protons. The negative charges belong to the orbital electrons. (The neutrons of the nucleus have nothing to do with the distribution of charge in the atom.)
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Figure 2. A simple electric circuit.
The dry cell produces a positive (+) charge at one of its terminals and a negative (Ð) charge at the other. These charges cause electric current to flow.
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Figure 3. Electron flow in a simple circuit.
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Figure 4A. The 3 parts of an electric circuit.
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Figure 4B. A simple electric circuit.
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Figure 5A. Electron flow with a complete electrical path.
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Figure 5B. No electrical flow with a broken electrical path.
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Figure 6. Polarity of source establishes direction of electron flow: load passes current in either direction. A source that is causing electron flow always sends out electrons through its negative terminal and takes them in through its positive terminal. Therefore, reversing the connections of the source in the circuit shown makes electrons flow through the lamp from B to A instead of from A to B.
