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Basic electrical concepts

  • Introduction to the fundamentals of electrical concepts.

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Basic Electrical Concepts Outline

  1. Introduction

  2. Electric Charge

  3. Electric Current

  4. Voltage

  5. Resistance

  6. Ohm's Law

  7. Energy

  8. Power

  9. Circuits

  10. Problem Solving

  11. Summary

Objectives

After studying this chapter, you should be able to:

  • Define voltage, current, and resistance.

  • Determine Ohm’s Law.

  • Describe the electric circuit.

  • Indicate the difference between AC and DC circuits.

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1. Introduction

  • Electronics History:

    • Discovery of electromagnetism (19th century): Hans Christian Oersted, Michael Faraday.

    • Development of electric telegraph by Samuel Morse and the telephone by Alexander Graham Bell.

    • Invention of vacuum tubes for amplification and rectification of signals used in radios, TVs, computers.

    • Mid-20th century: Invention of transistors by John Bardeen, Walter Brattain, and William Shockley.

    • Emergence of integrated circuits (ICs) and microprocessors in the 1970s, revolutionizing computing.

  • Applications of Electronics:

    • Consumer electronics, communication, transportation, healthcare, industrial automation, military, space exploration.

  • Principles of Electronics:

    • Based on electricity and magnetism, includes key components like semiconductors, transistors, ICs, and passive components.

    • Distinction between analog (continuous signals) and digital technology (binary code).

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2. Electric Charge

  • Basic Concepts:

    • Ordinary matter consists of atoms (nucleus: protons and neutrons; electrons in orbits).

    • Electric charge (q, Q) measured in Coulombs (C).

    • Two types of charges: Positive and Negative.

    • Electric force between charges: Opposite charges attract, like charges repel.

  • Electrostatic Force:

    • Force obeys Coulomb’s Law; the force between stationary charges.

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  • Quantization of Electric Charge:

    • Charge quantization: Smallest charge (charge quantum) is e = 1.6 × 10^-19 C.

    • Uncharged objects gain electrons (negatively charged) or lose electrons (positively charged).

    • Conservation of charge: Total charge in the universe is constant.

  • Masses and Charges of Atomic Particles:

    • Electron: Mass = 9.11 × 10^-31 kg, Charge = -1.6 × 10^-19 C.

    • Proton: Mass = 1.673 × 10^-27 kg, Charge = +1.6 × 10^-19 C.

    • Neutron: Mass = 1.675 × 10^-27 kg, Charge = 0.

  • Atomic Structure:

    • Nucleus diameter: 10^-15 to 10^-14 m; Electrons in a region of about 2 × 10^-10 m.

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3. Electric Current

  • Definition:

    • Electric current is the flow of electric charge; defined as the rate of charge flow across a surface area.

  • Measurement:

    • SI unit of current is the ampere (A): 1 A = 1 Coulomb/second.

    • Current can be instantaneous or average, depending on the time interval.

  • Flow Direction:

    • Current flows in the direction of positive charge movement; actual charge carriers (electrons) flow oppositely.

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4. Voltage

  • Definition:

    • Voltage (V) is the difference in electric potential between two points; measured in Volts (V).

  • Energy Measurement:

    • Voltage represents energy gained/lost moving charge across elements.

5. Resistance

  • Definition:

    • Resistance is the ratio of voltage to current; measured in ohms (Ω).

  • Resistor:

    • Electrical device designed to have a specific resistance value.

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6. Ohm's Law

  • Law:

    • Describes the relationship between voltage (V), current (I), and resistance (R).

    • Formula: V = I × R.

  • Sign Convention:

    • Attention to current direction and voltage polarity is essential.

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7. Energy

  • Definition:

    • Energy is the capability to perform work; commonly transformed into heat.

  • Joule's Findings:

    • Heat production is proportional to the square of the current and the time.

    • Formula: W = I^2R.

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8. Power

  • Definition:

    • Power is the rate of work done or energy dissipated; measured in watts (W).

  • Formula:

    • P = W/t = VI (Voltage × Current).

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9. Circuits

  • Definition:

    • An electric circuit is a network of electrical elements.

  • Types:

    • Passive elements (resistors, capacitors) and active elements (batteries, generators).

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10. Problem Solving

  • Practicing calculations relevant to electric charge, current, voltage, and power.

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11. Summary

  • Overview of key concepts and definitions essential for understanding basic electrical concepts, including Ohm's Law, the importance of voltage and current, power calculations, and circuit analysis.

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Bibliography

  1. Abhaya Kumar Behera, Basic Electrical Engineering, Department of KIIT Polytechnic BBSR, 2010.

  2. Albert Malvino, David Bates, Patrick Hoppe, Electronic Principles, 9th ed. McGraw Hill, 2021.

  3. Charles K. Alexander, Matthew N.O. Sadiku, Fundamentals of Electric Circuits, 4th ed. McGraw Hill, New York, 2009.

  4. Christopher R Robertson, Fundamental Electrical and Electronic Principles, 3rd ed. Elsevier, Oxford, UK, 2008.

  5. Hongshen Ma, Fundamentals of Electronic Circuit Design, University of Cambridge, 2005.

  6. Ibraheem Nasser, Electric Charge, 2017.