HISTORY OF ELECTRICITY

 

HISTORY OF ELECTRICITY

History of Electricity

The history of electricity spans several centuries and involves numerous discoveries and inventions. Here's a brief overview of the key milestones in the history of electricity:

 

1. Ancient Discoveries: The ancient Greeks, Egyptians, and Mesopotamians were aware of certain electrical phenomena, such as static electricity produced by rubbing amber or fur. However, their understanding was limited to these basic observations.
2. Electrostatics (17th and 18th centuries): In the 17th and 18th centuries, scientists like Otto von Guericke, Charles-François de Cisternay du Fay, and Benjamin Franklin conducted experiments and made important contributions to the field of electrostatics. Franklin's famous kite experiment in 1752 demonstrated the link between lightning and electricity.
3. Voltaic Pile (1800): Italian physicist Alessandro Volta invented the first practical battery, known as the voltaic pile. The voltaic pile consisted of alternating layers of zinc and copper discs separated by cardboard soaked in saltwater. It provided a continuous flow of electric current.
4. Electrochemistry and Electromagnetism (early 19th century): Humphry Davy and Michael Faraday conducted groundbreaking research in the early 19th century. Davy's work with electrolysis led to the discovery of several chemical elements. Faraday's experiments laid the foundation for the understanding of electromagnetism and electromagnetic induction.
5. The invention of the Electric Motor and Generator (1831): Michael Faraday's work on electromagnetic induction led to the invention of the electric motor in 1831. Faraday's experiments demonstrated that an electric current could be generated by moving a magnet near a wire, leading to the development of electric generators.
6. Development of Electrical Distribution Systems: In the late 19th century, the practical application of electricity began with the development of electrical distribution systems. Thomas Edison and Nikola Tesla played significant roles in advancing the field. Edison's direct current (DC) system and Tesla's alternating current (AC) system became rivals in the "War of the Currents," with AC ultimately prevailing due to its ability to transmit electricity over long distances.
7. Electric Lighting (late 19th century): Edison is credited with the invention of the practical incandescent light bulb in 1879. This breakthrough made electric lighting accessible and helped pave the way for the electrification of cities.
8. Expansion of Electricity Networks: In the late 19th and early 20th centuries, electricity networks expanded rapidly, providing power to homes, businesses, and industries. Power plants were built to generate electricity, and infrastructure such as transmission lines and substations were developed to distribute it.
9. Development of Electrical Appliances: The availability of electricity led to the development of various electrical appliances, including refrigerators, washing machines, radios, televisions, and computers. These appliances transformed daily life and contributed to the rise of modern living standards.
10. Advancements in Power Generation and Renewable Energy: In recent decades, there have been significant advancements in power generation, including the use of fossil fuels, nuclear energy, and the growing adoption of renewable energy sources such as solar and wind power. These advancements aim to reduce dependence on non-renewable resources and mitigate the environmental impact of electricity generation. 

The history of electricity is a vast and ongoing field of research and innovation. The discoveries and inventions mentioned above represent key milestones in our understanding and application of electricity, shaping the modern world in which we live.

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Lightning and urban lighting are some of the most dramatic effects of electricity

Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges, and many others.

The presence of either a positive or negative electric charge produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. In most applications, a force acts on a charge with a magnitude given by Coulomb's law. Electric potential is typically measured in volts.

Electricity is at the heart of many modern technologies, being used for:

• Electric power is where electric current is used to energize equipment;
• Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies.

Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the 17th and 18th centuries. The theory of electromagnetism was developed in the 19th century, and by the end of that century, electricity was being put to industrial and residential use by electrical engineers. The rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the Second Industrial Revolution. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.

History

Thales, the earliest known researcher into electricity

Long before any knowledge of electricity existed, people were aware of shocks from electric fish. Ancient Egyptian texts dating from 2750 BCE referred to these fish as the "Thunderer of the Nile", and described them as the "protectors" of all other fish. Electric fish were again reported millennia later by ancient Greek, Roman, and Arabic naturalists and physicians. 

Ancient cultures around the Mediterranean knew that certain objects, such as rods of amber, could be rubbed with a cat's fur to attract light objects like feathers. Thales of Miletus made a series of observations on static electricity around 600 BCE, from which he believed that friction rendered amber magnetic, in contrast to minerals such as magnetite, which needed no rubbing. Thales was incorrect in believing the attraction was due to a magnetic effect, but later science would prove a link between magnetism and electricity. According to a controversial theory, the Parthians may have had knowledge of electroplating, based on the 1936 discovery of the Baghdad Battery, which resembles a galvanic cell, though it is uncertain whether the artifact was electrical in nature.

Benjamin Franklin conducted extensive research on electricity in the 18th century, as documented by Joseph Priestley (1767) History and Present Status of Electricity, with whom Franklin carried on extended correspondence.

Electricity would remain little more than an intellectual curiosity for millennia until 1600, when the English scientist William Gilbert wrote De Magnete, in which he made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber. He coined the Neo-Latin word electricus ("of amber" or "like amber", from ἤλεκτρον, elektron, the Greek word for "amber") to refer to the property of attracting small objects after being rubbed. This association gave rise to the English words "electric" and "electricity", which made their first appearance in print in Thomas Browne's Pseudodoxia Epidemica of 1646.

Further work was conducted in the 17th and early 18th centuries by Otto von Guericke, Robert Boyle, Stephen Gray, and C. F. du Fay. Later in the 18th century, Benjamin Franklin conducted extensive research in electricity, selling his possessions to fund his work. In June 1752 he is reputed to have attached a metal key to the bottom of a dampened kite string and flown the kite in a storm-threatened sky.

Michael Faraday's discoveries formed the foundation of electric motor technology.

In 1775, Hugh Williamson reported a series of experiments to the Royal Society on the shocks delivered by the electric eel; that same year the surgeon and anatomist John Hunter described the structure of the fish's electric organs. In 1791, Luigi Galvani published his discovery of bioelectromagnetics, demonstrating that electricity was the medium by which neurons passed signals to the muscles. Alessandro Volta's battery, or voltaic pile, of 1800, made from alternating layers of zinc and copper, provided scientists with a more reliable source of electrical energy than the electrostatic machines previously used. The recognition of electromagnetism, the unity of electric and magnetic phenomena, is due to Hans Christian Ørsted and André-Marie Ampère in 1819-1820. Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analyzed the electrical circuit in 1827. Electricity and magnetism (and light) were definitively linked by James Clerk Maxwell, in particular in his "On Physical Lines of Force" in 1861 and 1862.

While the early 19th century had seen rapid progress in electrical science, the late 19th century would see the greatest progress in electrical engineering. Through such people as Alexander Graham Bell, Ottó Bláthy, Thomas Edison, Galileo Ferraris, Oliver Heaviside, Ányos Jedlik, William Thomson, 1st Baron Kelvin, Charles Algernon Parsons, Werner von Siemens, Joseph Swan, Reginald Fessenden, Nikola Tesla, and George Westinghouse, electricity turned from a scientific curiosity into an essential tool for modern life.

In 1887, Heinrich Hertz discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1905, Albert Einstein published a paper that explained experimental data from the photoelectric effect as being the result of light energy being carried in discrete quantized packets, energizing electrons. This discovery led to the quantum revolution. 

The first solid-state device was the "cat's-whisker detector" first used in the 1900s in radio receivers. A whisker-like wire is placed lightly in contact with a solid crystal (such as a germanium crystal) to detect a radio signal by the contact junction effect. In a solid-state component, the current is confined to solid elements and compounds engineered specifically to switch and amplify it. Current flow can be understood in two forms: as negatively charged electrons, and as positively charged electron deficiencies called holes. of transistor technology. The first working transistor, a germanium-based point-contact transistor, was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947, followed by the bipolar junction transistor in 1948.

Concepts

Electric charge

Charge on a gold-leaf electroscope causes the leaves to visibly repel each other

The presence of charge gives rise to an electrostatic force: charges exert a force on each other, an effect that was known, though not understood, in antiquity.  A lightweight ball suspended by a fine thread can be charged by touching it with a glass rod that has itself been charged by rubbing with a cloth. If a similar ball is charged by the same glass rod, it is found to repel the first: the charge acts to force the two balls apart.

Electric current

The movement of electric charge is known as an electric current, the intensity of which is usually measured in amperes. Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current. Electric current can flow through some things, electrical conductors, but will not flow through an electrical insulator.

Electric field

The concept of the electric field was introduced by Michael Faraday. An electric field is created by a charged body in the space that surrounds it, and results in a force exerted on any other charges placed within the field. The electric field acts between two charges in a similar manner to the way that the gravitational field acts between two masses, and like it, extends towards infinity and shows an inverse square relationship with distance. However, there is an important difference.

Electric potential

A pair of AA cells. The + sign indicates the polarity of the potential difference between the battery terminals.

The concept of electric potential is closely linked to that of the electric field. A small charge placed within an electric field experiences a force, and to have brought that charge to that point against the force requires work. The electric potential at any point is defined as the energy required to bring a unit test charge from an infinite distance slowly to that point. It is usually measured in volts, and one volt is the potential for which one joule of work must be expended to bring a charge of one coulomb from infinity. This definition of potential, while formal, has little practical application, and a more useful concept is that of electric potential difference, and is the energy required to move a unit charge between two specified points.

Electromagnets

Magnetic field circles around a current

Ørsted's discovery in 1821 that a magnetic field existed around all sides of a wire carrying an electric current indicated that there was a direct relationship between electricity and magnetism. Moreover, the interaction seemed different from gravitational and electrostatic forces, the two forces of nature then known.   Ørsted's words were that "the electric conflict acts in a revolving manner." The force also depended on the direction of the current, for if the flow was reversed, then the force did too.

Electric circuits

A basic electric circuit. The voltage source V on the left drives a current I around the circuit, delivering electrical energy into the resistor R. From the resistor, the current returns to the source, completing the circuit.

The components in an electric circuit can take many forms, which can include elements such as resistors, capacitors, switches, transformers, and electronics. Electronic circuits contain active components, usually semiconductors, and typically exhibit non-linear behavior, requiring complex analysis. The simplest electric components are those that are termed passive and linear: while they may temporarily store energy, they contain no sources of it and exhibit linear responses to stimuli.

Electric power

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.

Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used colloquially to mean "electric power in watts."