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Electricity - History and Basic Theory

Updated on November 21, 2014
Statue of Hans Christian Orsted
Statue of Hans Christian Orsted | Source

Electricity

This article presents in simple terms the history and basic theory of electricity with the aim to bring the science and technology to the understanding of ordinary people.

Electricity has driven the Second Industrial Revolution and continues to shape our culture and yet basic understanding of this phenomenon lacks to most people except those trained in the industry.

Modern science of electricity had been evolving in the past 300 - 500 years. Today electricity is part of our culture. We all need to have the basic understanding of where we came from regarding electricity and where we are now.

Electricity is a natural effect that had been experienced by human beings since antiquity, most likely through lightning, statics and in our biological make-up, fish exhibit electricity effects more than any other animal.

Histroy Of Electricity Through The Ages

  1. Ancient Times: Electricity as a natural phenomenon had been observed in fish - Ancient Egyptian texts refer to certain fish as "Thunderer of the Nile" due to their electric effects.
  2. 1500: The Arabs use the term raad a term for lightning to refer to the electric ray (a type of fish that produces an electric discharge) thereby providing the earliest link between lightning and electricity
  3. 1600: William Gilbert coined the Latin term electricus to refer to electricity.
  4. Further work by Otto von Guericke, Robert Boyle, Stephen Gray, C.F. du Fay followed.
  5. 1752: Benjamin Franklin, an American statesman, carried out extensive experiments on electricity which he sponsored using his personal fortune. He carried out one very dangerous experiment which proved that lightning was indeed an electrical phenomena.
  6. 1791: Luigi Galvani demonstrated that electricity was the medium through which nerve cells transmitted messages to the muscles.
  7. 1800: Alessandro Volta created the voltaic pile, a stack of zinc plates alternating with copper plates to produce the first reliable source of electricity. The battery, before that electricity was produced by some static electricity generators.
  8. 1820-1821: Hans Christian Orsted and Andre-Marie Ampere: Orsted demonstrated that electrical current produced magnetism, Ampere developed and refined the mathematical structure: these two demonstrated the unity of magnetism and electricity.
  9. 1821: Michael Faraday invented the electric motor.
  10. 1827: Georg Ohm provided the first mathematical analysis of the electric circuit.
  11. 1861 and 1862: James Clerk Maxwell in his paper " On Physical Lines of Force" demonstrated that electricity, magnetism and light were one phenomenon in a set of equations, the famous Maxwell's Equations , which are considered as some of the most fundamental in the description of nature.
  12. Late 19th century was the beginning of electrical engineering as separate from the early scientific interest and the following scientists were the pioneers of practical application of electricity:
  • Alexander Graham Bell
  • Otto Blathy
  • Galelio Ferraris
  • Oliver Heaviside
  • Anyos Jedlik
  • Lord Kelvin
  • Sir Charles Parsons
  • Ernst Werner Siemens
  • Joseph Swan
  • Nikola Tesla
  • George Westinghouse

As said above, the late 19th century scientists were engineers who transitioned the study from a mere curiosity to a commercial and cultural concern necessary for ordinary day life. The Second Industrial Revolution was driven by electricity.

In 1887 Heinrich Hertz discovered the photoelectric phenomenon and it was left for Albert Einstein to explain in 1905 it as a quantum process, earning himself a Nobel Prize.

Progress continues up today.

Bibliography:

1. http://en.wikipedia.org.wiki/Electricity

Nature of Electricity

Electricity occurs naturally in two forms, as static electricity or as electrical current. Electrostatics is the study of charged bodies where there is isolation of charge or a body where charge is stored.

When there is a discharge, then an electrical current flows. Therefore electricity can be said as flow of electric charge.

Generation

Drax Power Station 660MW Generator:m This is unit no2 Generator one of six
Drax Power Station 660MW Generator:m This is unit no2 Generator one of six | Source

Electromagnetism Theory

The basic theory necessary for our discussion in this article is that discovered by Orsted and mathematically refined by Ampere. This can be stated as follows:

  • An electrical current produces a magentic field and
  • A changing magnetic field produces an electrical current
  • Interacting current carrying conductors produce mechanical force (of attraction or repelling)

Understanding these three principles will be useful throughout this article to show how things work. Theory will be kept to the minimum , only that required to understand how electricity works .

Generating Electricity From A Changing Magnetic Field

A basic high school science experiment involves

  • two magnets placed facing each other
  • a copper wire placed between the two magnet ends and connected to a current measuring equipment or to a light bulb and the students to conduct and observe the experiment
  • at least one of the students must move (i) either the set of magnets up and down or (ii) the wire
  • It will be observed that when the wire is moved up and down between the magnet poles, the light bulb will light up. The same observation is made if the the conductor was moved instead of the magnet

The experiment demonstrates that : moving a conducting wire across a magnetic field produces electricity.

Or: a changing magnetic field produces electricity.

Also to be observed is that kinetic energy can be converted to electrical energy.

Wind Power - Example of Mechanical Energy Convertion to Electrical Energy

Wind Farm on Columbia Hills
Wind Farm on Columbia Hills | Source

Definitions & Formulae

Quantity
Definition
Unit
Charge, q
Basic Unit of Electricity, either positive or negative
Coulomb
,Current, I
Rate of flow of charge per unit time, I = q/t
Amperes
Voltage , Potential Difference, V
The energy required to move a unit charge from one point in a circuit to another, E = q x V
Volt
Power , P
Rate of conversion of energy from one form to another, P = E/t = (q x V)/t = IV = IxIxR (I squared R)
Watts
Resistance, R
Relationship between the Voltage across a passive component and Current flowing through it R = V/I
Ohms

Producing Magnetism From Electric Current

Another high school experiement involves the following:

  • Iron filings
  • A copper conductor connetected to a source of electricity
  • Students to monitor and record

It will be observed that when the switch is closed and current is flowing, if the iron filings are placed near the conductor, they will align as if a magnet was near them.

The experiement proves that an electrical current produces magnetism.

Interacting Current Carrying Conductors Produces Mechanical Force

Two current carrying conductors placed side by side will either pull or repel each other depending on the direction of currents.

This effect is a direct consequence of the fact that a current carrying conductor will will produce magnetic effect. Therefore two current carrying conductors will have interacting magnetic fields.

The practical implication is that electrical energy can be converted to kinetic (mechanical ) energy.

Ampere's Law

Ampere Force Law
Ampere Force Law | Source

Electrical Switchgear

Electrical Power Substation
Electrical Power Substation | Source
Substation Bolsward, The Netherlands
Substation Bolsward, The Netherlands | Source

Electrical Equipment

Equipment
Functionality
Notes
Generator
Production of electrical energy from mechanical energy
In a generator, three things happen, an electrical current produces a magnetic field. A mechanical power system drives rotor to create a changing magnetic field and thus the varying magnetic field produces electricity
Transformer
Stepping up or stepping down voltage from one voltage level to another
A transformer is an example of an electromagnetic equipment where a varying electrical current produces a varying magnetic field which in turn produces a varying electrical current!
Transmission lines
Bulk transfer of electrical energy
A typical electromagnetic wave
Electrical motor
Production of mechanical energy from electrical energy
Typical case of two current carrying conductors

Electrical Power Lines

Source

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    • mgt28 profile image
      Author

      mgt28 3 years ago

      Dear ilikegames,

      Thanks for your affirmation. Electricity is a fascinating phenomena. It is still puzzles me also.

    • ilikegames profile image

      Sarah Forester 3 years ago from Australia

      Love the hub, I'm not usually very good at understanding these sort of things but you've done a good job communicating your points. Reminds me of all the fun experiments we did in school with currents and electricity!

    • mgt28 profile image
      Author

      mgt28 3 years ago

      torrilyn , your comment is appreciated. Glad to hear that this was useful.

    • torrilynn profile image

      torrilynn 3 years ago

      Thanks for the information on electricty, how it started, and the history lesson. Voted up.

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Hi Mike ,

      Thank you for reading, your affirmation is very important as I am trying to write scientific hubs in a way that everyone can understand.

    • Mike Robbers profile image

      Mike Robbers 3 years ago from London

      @mgt28 : Very well written hub, educational and full informative. Taught me a lot of things i wasn't aware of, thanks for sharing..

      Voted up

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Dear Nasrullah, thanks for passing by and reading. Indeed electricity is very dangerous. Thankfully, at low voltage we can do experiments. People who do experiments must have knowledge of safety , earthing and first aid. Batteries and small dynamos like that of bicycle are good for experiments. Domestic supply must only be used for experiments in school by trained teachers.

    • Nasrullah idris profile image

      Nasrullah Idris 3 years ago from Bandung

      I often see parents give to their children the impression that "electricity is identical with something dangerous". Though not always the case. Electricity to low voltage, such as five volts, can be made the object of the game is based education.

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Dear Mel, thank you for your affirmation. My hope is to make it easy for everyone to understand in a less mathematical form what makes our world what it is today. We owe it to those before us, who over time observed, measured and communicated their findings.

    • Mel Carriere profile image

      Mel Carriere 3 years ago from San Diego California

      A SHOCKING expose on the history of electricity. Your writing style is very succinct and comprehensible for we the scientifically challenged. Great hub!

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Shiley, thank you for reading. Your positive comments are appreciated I hope many people will know the history and understand the basics of electricity.

    • Shiley profile image

      Karen Shiley 3 years ago from Washington

      Fun read and a nice introduction to electricity.

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Hi JPSO138, thanks for encouraging comment. I am glad to receive such affirmation from you.

    • JPSO138 profile image

      JPSO138 3 years ago from Cebu, Philippines, International

      Well research hub and very informative.. Surely no need for second thoughts. Up for this one..

    • mgt28 profile image
      Author

      mgt28 3 years ago

      Thanks electronician for reading and comments. I hope there will be a future where these subjects will be easily explained by many without resorting to Maths!

    • electronician profile image

      Dean Walsh 3 years ago from Birmingham, England

      An excellent introduction to electrical science and an interesting read, voted up!