EET 251

Electricity and Electronics

Lesson One

BASICS OF ELECTRICITY

Electricity is a fascinating science that we use in many different ways. It would be difficult to think of the many ways that we use electricity each day. It is important to have an understanding of electricity and its applications.

This lesson deals with basic topics in the study of electricity. These include the discovery of electricity, basic electrical systems, energy and power, the structure of matter, electrical charges, static electricity, electrical current, voltage, resistance, and electrical safety.

Each lesson contains important terms to know and understand as well as review questions to answer at home or during class.

1.1 History of Electricity and Electronics

Thales of Miletus and “magnetism”

Compasses and the use of lodestones

William Gilbert

Benjamin Franklin: positive and negative charges, the transfer of electricity

Alessandro Volta: the voltaic pile or battery

Charles de Coulomb: electrical quantities

Michael Faraday: electrode, anode, cathode, ion

Heinrich Herts: electromagnetic waves

Guglielmo Marconi: wireless telegraph

Hans Christian Oersted: electromagnet

Thomas Edison: telegraph, phonograph, incandescent lamp, electrical-power generation system

Alexander Graham bell: telephone

Lee de Forest: improvements on the vacuum tube

Invention of the transistor

1.2 Electrical Systems

Graphical representations of electrical systems: electrical system block diagram

The “systems” concept

Parts of the electrical system: source, path, control (full and partial control), load, indicator

Transformers

Energy conversion

1.3 Energy, Work and Power

Energy, kinetic energy and potential energy

Work

Power, watt (unit of measure)

1.4 Structure of Matter

Matter: solid, liquid, and gaseous states

Element, table of the elements

Compound

Molecule

Atom: electron, proton, and neutron; hydrogen atom, nucleus, orbits or circular paths, atomic number, mass of protons and electrons

Atomic orbitals, shells, valence shells and valence electrons, covalent bonding and the overlapping of valance shells

Pattern followed in the placement of electrons in the atom, active/stable atoms

Atom combination

1.5 Electrical Charges

Electrostatic charges, attraction and repulsion principles

Electrostatic field

Charged materials

Lines of force

Gravitational field

1.6 Static Electricity

Static electricity and current electricity

Practical uses of static electricity: Van de Graaf generator, electrostatic filters

1.7 Electrical CurrentElectrical current and electrical current flow

Conductors, materials that are good conductors

Insulators, materials that are good insulators

Semiconductors

Superconductors

Free electrons

Electrical circuits, closed/open circuits, short circuit

Direction of current flow: electrical current flow, conventional current flow

Amount of current flow: coulomb, ampere

1.8 Electrical Force

Voltage and volts

1.9 Resistance

Factors that influence resistance of materials:

(1) number of free electrons

(2) Material’s composition

(3) Length of the material

(4) Cross-sectional area

(5) Temperature

1.10 Voltage, Current, and Resistance

Definitions and symbols for voltage, current and resistance

1.11 Volts, Ohms, and Amperes

Definitions and symbols for volts, ohms, amperes

Voltmeter, ampmeter, ohmmeter

1.12 Electrical Safety

Considerations for the physical environment in the electrical lab or work area:

(1) Well-designed equipment

(2) Work surfaces and floors covered with nonconducting material

(3) Fire extinguisher

(4) Electrical circuits and equipment plainly marked

(5) Tools with insulated handles

(6) Three-wire cords and plugs

(7) Adequate lab space and proper ventilation, heat and light

(8) Safe shop practices (low voltage, supervision, etc)

(9) First-aid kit

(10) Reporting incidents

1.13 Careers in Electronics

Service Technician

Field Engineering Technician

Technologist

Engineering Assistant

Technical Writer

Electronics Sales

Computer Technician

REVIEW

1. How was electricity discovered?

2. What are the five parts of any electrical system?

3. Discuss each of the parts of an electrical system.

4. What are some types of energy?

5. What is work?

6. What is power?

7. What are the three types of matter?

8. What are elements, compounds, and molecules?

9. Discuss the three types of particles that make up atoms.

10. Discuss the terms orbit and valence electrons.

11. Discuss electrostatic charges.

12. What are some applications of static electricity?

13. What are conductors, insulators, semiconductors, and superconductors?

14. What is (a) and open circuit, (b) a closed circuits, and (c) a short circuit?

15. Discuss conventional current flow and electron current flow. Which type is used in this book?

16. How does electrical current flow compare with water flow in a pipe?

17. What is voltage?

18. What is resistance?

19. What factors determine the resistance of a material?

20. List at least five important things to remember about electrical safety.

21. List at least five careers in which a knowledge of electricity and electronics is needed.