A Brief Course and History of Electricity
By Lawrence Hardy of None
A Brief Course on Electricity
Thus far, we have traced the origins of the computer from late Medieval Europe to the 20th century. It seems only fitting to examine briefly the history, inventions, and people that made possible the harnessing electricity and electronics to power the modern digital computer. Since the dawn of civilization, lightning (electricity) has aroused the curiosity of humans. The Ancient Greeks imagine the bolts of lightning as the wrath of Zeus – king of the gods on Mount Olympus. The etymology of electricity shows that it evolved from the Greek word elektron – meaning amber. In her book Empire of Lights (2003) Jill Jonnes recounts how Thales, in 600 B. C., discovered amber when rubbed briskly with a cloth became magnetic attracting leaves, straw, and feathers.
It would be more than two thousand before William Gilbert of London would replicate the experiments of Thales with amber. Gilbert’s testing did not stop with amber. He performed the same tests with a number of materials glass, rock crystal, sulfur, sealing wax. Gilbert called the phenomena of static electricity “electrical effluvia.”
Otto von Guericke follows Gilbert in the progression of human interaction with electricity. More famous for his work with the vacuum, von Guericke invented the first electrostatic generator in 1661 in Magdeburg, Germany. I was not until 1709 that Francis Hawksbee of England reproduced von Guericke’s experiment generating static electricity with a hollow glass sphere excited with rubber instead of sulfur sphere excited by rubbing (Jonnes, 2003).
Only in recent history – from the Renaissance forward – has humankind discovered how to harness the mysterious power of electricity. The first of these discoveries came with the invention of the Leyden jar, by Dutch scientist Pieter van Musschenbroek, in 1745. The Leyden jar was one of the first known capacitors. The capacitor or condenser – as it was originally named – is a passive electronic device that holds a charge in an electrostatic field. A capacitor is not to be confused with a battery, which generates its own electricity internally. A capacitor instead receives the charge from an external source.
These early capacitors provided many opportunities for the user to demonstrate the power of electricity without the need of an electrostatic generator. A typical Leyden jar consisted of a glass jar partially filled with water sealed with a cork at the top. A thick conducting wire (brass or copper) capable of storing a significant amount of electric charge protruded through the cork. The Leyden jar received its initial charge by bringing it into contract with an external source, in the 18th century a friction-generating machine (Virtual Museum of Old Electric, Electronic, and Electrochemical Instruments, 2009).
The next milestone in the domestication or controlling of electricity occurs when Benjamin Franklin, one of the Founding Fathers of the United States, who was able to prove that electricity and lightning (Abbott, 1981). Franklin had long thought lightning was a natural occurrence of electric current. He had observed the similarities between the lightning and manmade electricity. To prove that they were one in the same he decided to see if lightning would pass through metal. The story of how he did it by flying a kite in a thunderstorm to electrify a key is taught to every elementary school age child in the United States.
Franklin invented the lightning rod to protect homes and ships from the damage caused by lightning (Library of Congress, 2009). However, Franklin’s hypothesis describing electricity as a fluid proved wrong. He based his theory on the fact that an object electrical charge changes when rubbed. It either gains or loose electricity becoming either positively or negatively charge. Objects with opposite charges attract each other; those with the same charge repel. Franklin error is because the components of the atom – protons, electrons, and neutrons – had not been delineated. Today some modern historians believe Franklin was referring to the atom and the flow of electrons from negative to positive (ABC-CLIO, 2003) .
Another step towards the control of electricity as it is comprehended in the 21st century occurs with the invention of the battery by Italian physicist Alessandro Volta in 1800. Unlike the Leyden jar, which required an external source to obtain an electrical charge, Volta’s battery created electrical energy internally. The voltaic pile, as the battery came to be known, relied on conversion of chemical energy into electricity. The voltaic pile consisted of alternating disks of zinc and copper or silver with each pair separated by brine soaked cardboard. The Voltaic battery provided the first practical method of generating a continuous stream of electricity. The Voltaic battery was also the first electric circuit. NASA provided the image of a 20th century replica of Volta’s battery in Figure – 21 (Smithsonian Institution Libraries, 2001).
The battery invented by Volta was a wet cell battery. In 1836, British scientist John F. Daniel invented a dry cell battery. A dry cell battery is a battery with an electrochemical cell with low-moisture content or a pasty electrolyte. An electrolyte is any substance containing free ions that behaves as an electrically conductive medium. The most common electrolytes are salts, acids, and bases (the opposites of acid).
Following in the footsteps of Volta and other scientists was Michael Faraday who is best remembered for his understanding of electromagnetism. Faraday built the first electric motor in 1831 when he discovered that moving a magnet inside wire coil created electricity. He later built the first generator and transformer.
The first practical application of electricity was the telegraph, invented first in Great Britain by Charles Wheatstone and William Cooke in 1837. The Cooke-Wheatstone Telegraph required six wires and five magnetic needles to create messages. Messages created by The Cooke-Wheatstone Telegraph deflected the five needles either left or right to indicate letters (Derfler & Freed, 2002) (Hardy, 2008). That process however was passed over in favor the Samuel F. B. Morse 1844 telegraph system, which was much simpler mechanically and easier to use. Instead of needles it utilized combinations of on and then off (circuit open, circuit closed) circuit to represent letters and numbers.
The next scientific triumph over electricity was Alexander Graham Bell’s Telephone invented in 1876, also of the United States. That invention was followed quickly by Thomas Alva Edison’s incandescent electric lamp (light bulb) in 1879.
History tells us that a number of inventors proceeded Edison’s light bulb Frederick de Moleyns of England in 1841, Jean Eugene Robert-Houdini in 1851, and Alexander Nikolayevich Lodygin in 1872. It was British scientist Sir Joseph Wilson Swan with the assistance of Charles Stearn whose light bulb invention in 1878, legend credits Thomas Alva Edison of the United States with the invention of the light bulb (lamp) in 1879. When Edison brought his light bulb to England, he was forced to merge with the company Swan created or face a patent infringement lawsuit. In 1881, Edison purchased the Wilson patent for the electric lamp.
What makes Edison unique in American history was his astute business acumen and practical understanding of electricity and. An example of Edison’s light bulb is shown in Figure – 22, image provided by the Smithsonian Institution. Thomas Alva Edison
We study briefly Edison’s life not because of his 1000 patents but because of his light bulb, which was the predecessor to the vacuum tube, his teletype was the predecessor to ASCII, and for the Edison effect or thermionic emission. Thermionic emissions in a vacuum tube – during the infancy of radio – convert alternating current to direct current actuate a meter or a telephone receiver. These three patents had a significant effect on the future of electronic calculators later dubbed computers
Thomas Edison was the most prolific inventor in American history receiving patents on more than 1000 inventions. He was born on February 11, 1847 in the town of Milan, Ohio, the seventh of seven children. During the Civil War, Edison learned about the characteristics of electricity working on the train line between Port Huron and Detroit selling newspapers and sundries and reading books he borrowed from the library.
By 1868, at age 21, he received his first patent for the telegraphic vote-recording machine. The following year, he invented an improved version of the stock ticker tape by creating the printing telegraph. The Edison version of the stock ticker tape printed stock quotations and gold prices in plain text rather than Morse code. The Edison printing telegraph under glass became the iconic symbol of Wall Street. For printing telegraph, Edison received $40,000, which is the equivalent to $500,000 in 2008.
In 1876, Edison established his research laboratory at Menlo Park, New Jersey. It was the first of its kind, a laboratory dedicated to industrial research in the field of electricity. After the establishment of Menlo Park laboratory, Edison did not disappoint. Starting in 1877, Edison demonstrated his genius when he received a patent for improvements to the Bell telephone speaker. A year later, Edison invents of the phonograph. For his creative ingenuity, a gracious public gave him the nickname “Wizard of Menlo Park.”
When Edison created his version of the electric lamp, a number of cities had already granted franchises to local utility companies to light their streets. Many American and European cities chose the electric arc lamps for public lighting. New York, London, and Paris were the most prominent cities using the arc lamp technology. The arc light had several drawbacks. Foremost among them was its unsuitability for use indoors. Second, the power used to produce arc lights was alternating current (AC), considered very dangerous in 1880, especially when suspended over public or under thoroughfares without the proper insulation. Third, arc lights flickered at such irregular intervals that it was annoying. Finally, arc lights required constant maintenance and replacement.
The alternative to arc lights was gaslight. Gaslights proved to be a thriving industry. Many cities and towns across the United States relied on gaslights for both residential lighting and heating as well as lights for public safety. These cities – Baltimore the most prominent – had set up utility commissions, which granted franchises to local companies to provide gas to the public. By the late 19th century, the gas lighting and heating infrastructure provided most of the conveniences of the modern incandescent light.
To seduce customers away from the gas utilities, Edison began a marketing strategy, which stated the incandescent light provided a brighter, safer, and better way to light the home. To hasten the replacement of the power of the gas utilities, Edison purposely patterned his electric lighting utility parallel to the infrastructure of the gas utility. Wherever gas companies offered lighting, Edison would challenge by offering his incandescent light. Where gas companies laid pipes under the streets to distribute gas for indoor and outdoor use, Edison paralleled their efforts building power stations and laying underground conduits to carry electricity. Every convenience the gas lamp offered the customer, Edison planned to have his electric lamp to equal or surpass its gas counterparts (Smithsonian Institution, 2008).
In the months that followed the Menlo Park demonstration, Edison and his team designed and produced by hand, all the necessary components to make a viable electrical system infrastructure: sockets, fuses, switches, power meters, dynamos, and insulation for the wire that would connect customers. Despite his creativity, many of his financial backers refused to invest in a system that had yet to proven itself. Undaunted by the lack of support by established sources of financing, Edison was able to raise enough funds privately from friends and associates to complete his vision.
To highlight the efficiency and practicality of the electric lighting system, Edison chose to electrify the site at 255 and 257 Pearl Street in the heart of New York's financial district. On September 4, 1882, Edison introduced America to first electric generating power plant. It served one square-mile area – the limit a generator can send direct current –that included wealthy and influential customers: J.P. Morgan, the New York Stock Exchange, and a number of the nation's largest newspapers (WGBH/PBS, 2000).
In 1890, by combining his various enterprises, Edison had formed the Edison General Electric Company to sell a wide range of consumer products from electric light bulbs and lamps to electric heating. It was during this same period that a competitor for customers seeking direct current emerged, the Thomson-Houston Company. The Thomson-Houston Company was formed in 1883 when a group of investors from Lynn, Massachusetts led by Charles A. Coffin purchased the American Electric Company.
As both Thomson-Houston and Edison General Electric expanded into new economic frontiers, it became apparent to both companies that neither company individually could gather the necessary materials to produce a complete array of electrical appliances based entirely on its own technological competencies. More out of compromise, than necessity the two companies combined in 1892 to form the General Electric Company (GE) (General Electric, 2009). Edison would later sell his stock in the company to pursue other ventures (New York Times, 1892) such as motion pictures and the phonograph.
ELECTRIC CURRENT
Electric current is a basic form of energy that occurs both naturally and artificially. Examples of the most common naturally electric current are the polar Aurora Borealis created by the solar winds and lightning. The most naturally occurrence of lighting is during a thunderstorm. Lightning may also occur during a volcanic eruption or dust storm. A lightning bolt travels at a speed of 186,000 miles per second, with temperatures that approach 50,000 degrees F which hotter the surface of the sun.
Artificial electric current comes in two forms: stationary electricity also known as static electricity and moving electricity also known as current electricity. An example of an everyday occurrence of static electricity happens when person walks across a carpet, and creates a spark just before touching a metal knob or cabinet. A practical method of generating static electricity in the classroom occurs when the instructor demonstrates the power of electricity by rubbing a silk scarf across a rubber rod. An example of everyday occurrences of current or moving electricity is the flipping of a switch to turn on a light or other electrical appliance in your house. Current electricity is called moving electricity because it is continuous as oppose to the isolated discharges of static electricity.
Scientists and engineers group electric current into two subcategories: direct current (DC) and alternating current (AC). The names of the two forms of moving currents are demonstrative of their differences. The electrons produced in direct current flow in one direction. The current produced by batteries is an example of direct current. The electrons produced in alternating electricity flow in one direction then reverse and flow in the opposite direction. An example of alternating current is the electricity flowing through the wires of your home supplied by the local power company.
Direct Current
The heyday of direct current occurred with the perfection of the incandescent lamp by Thomas Edison in 1879. In the 1880s, in the United States direct current was synonymous with electricity although arc lights (streetlights used alternating current). Today, direct current is the exclusive domain of automobiles, semiconductors (memory chips), and microprocessors – used in personal computers, cellular telephones, MP3 players, and other small portable electronic devices.
The main benefit of direct current is that it flows in one direction – compared to that of alternating current that flows in two directions – therefore less dangerous than alternating current. The main drawback to widespread use of direct current was its transmission inflexibility. First, the maximum distance Edison could transmit a direct current charge was one mile. A second drawback to direct current electrification at the dawn of the 20th century was the lack of engineering techniques and skills to vary its voltage, to transform it from high voltage to low voltage and vice versa. For example, if the electricity required to electrify light bulbs in a factory was 60 watts, then the power transmitted by the power station was 60 watts. If machines at the same factory required 100 watts of power to operate, the factory owner had to buy from a source other than the provider powering the light bulbs. At the dawn of the 20th century, it was not economically feasible to electrify residential and industrial areas dynamo. In the 1960s, however, the conversion of direct current from high voltage to low voltage and vice versa ceased to be a problem. Science has bridged the technological differences that separated Tesla and Edison. Today, the only differences between the two power sources are the needs of the customer. Through the use of power converters that regulate the flow of current between electrical appliance, the worry over which form of electricity is most beneficial is moot.
Alternating Current
An alternating current is an electric current that reverses the flow of its energy or polarity at regular intervals. The current surges or flows in one direction until it builds to a maximum then drops down to zero. Then it surges or flows in the opposite direction, building to a maximum and once again dropping to zero. The two consecutive surges, one in each direction, is one cycle. The number of cycles repeated in the span of one second is the frequency in which the electricity flows. Alternating current displaced direct current as the standard for American and Canadian homes and industry in the 1880s. At the time, AC was more economical because of the invention of the transformer that raises or lowers the voltage to a desired level for use in the home, business, or industry.
Nikola Tesla
Although Edison pioneered the use of electricity in the home, for streetlights, and a number of other applications, Nikola Tesla’s genius and ingenuity in electrical engineering overshadowed that of the great Thomas Edison. Although he never won the Nobel Prize in Physics for his work with electricity, Tesla’s pioneering work with alternating current made the use of electricity practical and affordable for the electrification of America – in business, in the home, and for public safety. For his efforts, Tesla received the moniker “Father of Alternating Current.” In all, Tesla received hundreds of patients for his work in alternating currents, wireless transmissions, and florescent lights.
Nikola Tesla’s was born a subject of the Austro-Hungarian Empire on July 10, 1856 in a mountainous area of the Balkan Peninsula known as Lika. Tesla began his education at home then later attended school in Carlstadt, Croatia excelling in his studies along the way. At an early age as a child, Tesla showed his genius by solving mentally integral calculus problems.
For electricity created artificially, there are two basic categories alternating current (AC) and direct current (DC). The basic difference between alternating current and direct current is the way the electrons flow across the wires. First, with alternating current the flow of electrons is bidirectional flowing in one direction – like direct current – then reverse and flow in the opposite direction. Second, there is no one half mile limitations on the transmission of alternating current as there is with direct current.
The story of alternating current in the United States begins with the arrival of Nikola Tesla in New York in 1884. Armed with a letter from an Edison colleague of Edison, Charles Batchelor, as means of introduction, Tesla was able to gain an interview with Edison. At first, Edison scoffed at the recommendations Batcher made in the letter. However, after Tesla was able to elaborate his experiences electricity and electrical engineering, he won Edison over and received a tentative job offer to work at his Menlo Park laboratory if he could repair the dynamos installed on the SS Oregon at the New York shipyards. Yes indeed, replied a confident Tesla who traveled to the shipyards and went to work on the repairs immediately. Tesla worked through the night repairing the innumerable short circuits and circuit breaks on the ship. By dawn, with the assistance of the ship’s crew, he had finished.
Stunned by Tesla’s efficiency Edison gave Tesla a job at Menlo Park laboratory. His first assignment on the new job was to redesign the shop at Menlo Park. Tesla completed the task in about a year. Although a strong proponent of alternating current, Tesla kept busy by deducing methods to make Edison's direct-current dynamos more efficient. Tesla convinced Edison he would save of money, if let him redesigned the DC dynamos thereby making them more efficient. Edison – a shrewd businessman – and always interested in making money, agreed to Tesla's proposition. In exchange, if successful, Edison agreed to pay Tesla $50,000 if he could improve the efficiency dynamos. Several months later, after Tesla completed the work on the dynamos, He reported to job finished expecting the promised sum but Edison reneged on his promise. Stating that Tesla did not understand his offer of such a large sum of money was an offer in jest. Tesla did not see the humor in the explanation and immediately resigned his Menlo Park position (Morgan Reynolds Inc, 2005).
After leaving Menlo Park, he quickly formed several business partnerships. The first of these partnerships was with a group of investors offering to form the Tesla Light and Manufacturing Company. The investors wanted Tesla to focus on improving the system of arc lights already in use in many American and European cities. As mention previously, arc lights were fine for lighting public events and streets. However, they had several drawbacks, they were too expensive, too bright, unreliable, and too dangerous for the home. In addition, arc lights also had an annoying flicker.
On March 30, 1885, Tesla filed for his first patent, a design improvement of the arc lamp that addressed the major problems with the arc light, flickering, expense, and reliability. The newly formed Tesla Light & Manufacturing Company was a success and making money. However, when Tesla attempted to convince investors about the building of an electric motor, his investors informed him that they were not interested. To compound his difficulties with his new company, the investor refused to pay him for his improvements to the arc light. Broke and desperate, he took a job as a ditch digger to provide himself with food and shelter during the winter of 1886-1887 (Morgan Reynolds Inc, 2005).
Then in the spring of 1887, Tesla’s luck changed for the better when he met A.K. Brown of the Western Union Company. Brown had read about Tesla’s genius in a publication, the Electrical Review. Brown had recognized the advantages alternating current had over direct current and thought Tesla would be the perfect cornerstone. He quickly formed a partnership with Tesla then added attorney Charles Peck to the partnership to form the Tesla Electric Company. Later Peck was able to convince financier J. Pierpont Morgan to subsidize the Tesla Electric Company. Overjoyed by his newfound benefactors, Tesla threw himself into the job. He worked so furiously, that many of his colleagues worried about his health.
Soon, with the help of a friend, newly immigrated Anthony Szigeti, Tesla produced the three complete systems for utilizing alternating-current – a single-phase current used primarily for residential dwellings and two polyphase (more than one) currents – two-phase current and three-phase current – to deliver greater power where needed for commercial and manufacturing establishments.
Tesla and Szigeti built dynamos to generate the current, the motors that produced the power from them, and the foundation of his alternating current infrastructure, the Tesla Coil – a transformer for raising and lowering the voltage when needed. Tesla was reluctant to go public with his new inventions because of past ordeals first with Edison and later with the investors of Tesla Light and Manufacturing Company. He did not trust American businessmen. He wanted to be rewarded for his sacrifice. He obtained 40 patents for his alternating current apparatuses. After getting advice from his company’s patent attorneys, Tesla, on May 15, 1888, presented his theory, monograph to the membership AIEE (American Institute of Electrical Engineers), “A New System of Alternating Current Motors, and Transformers.”
Tesla carefully explained the possibilities of alternating current were endless: The basis of his treaties alternating current unlike direct current was flexible and unbound by transmission limitations. Direct current was inflexible and required a powerhouse at every mile of service. Copper conduits buried under the streets carried the current. Alternating current, on the other hand, can travel for hundreds of miles without losing strength, and requires no conduits. As Tesla explains, under his system, powerhouses in isolated places can generate electricity that is used hundreds of miles away. A single wire could carry a thousand of volts of electricity safely, many times more than possible with Edison's direct current methods. Then the key to the entire infrastructure, the transformer, the Tesla Coil, increases the voltage of as it leaves the power station and decreases the voltage to the appropriate level for safe delivery to homes or factories. The War of the Currents had begun. Tesla faced stiff competition from Edison (Morgan Reynolds Inc, 2005).
The War of the Currents
As the War of the Currents was a war of philosophy and technology more in line with the recent modern battles between proponents of VHS format and the Betamax format for video tape. More recently, the war waged by backers of Blue Ray technology against those in favor the HD technology as the primary format for high definition Digital Video Disks (DVD).
The war began when George Westinghouse of Westinghouse Electric Company of Pittsburgh joins forces with Tesla and his colleagues. Westinghouse, once a backer of Edison’s DC power, quickly switched to AC and never looked back when he learned of Tesla’s transformers and motors. Westinghouse was so enthralled with Tesla, that he offered to buy all of the Tesla's patents, which included the transformer and the motor for $60,000, plus 150 shares of Westinghouse stock, and pay Tesla S2.50 for each horsepower generated by his invention under the Westinghouse name.
The major fronts of the war were the campaigns used by the two factions. Westinghouse and Tesla took the high road using positive statements to sway public opinion in the favor of AC. While Edison, on the other hand, took the low road. Westinghouse using Tesla’s polyphase devices won the bid over the Edison General Electric Company to light the Chicago World’s fair, dubbed the Columbian Exposition. Westinghouse also won the bid to harness the kinetic power of Niagara Falls to illuminate Buffalo and New York City. The Westinghouse Electric company completed the project in 1896.
Edison’s campaign to persuade the public DC utilized fear mongering to frighten the public into believing alternating current was dangerous. Edison hired schoolboys to steal the pets of the residents of West Orange, New Jersey to demonstrate how danger of electrocution with alternating current. This mindset led Edison to recommend alternating current to the state of New York as a humane method of executing prisoners. Edison also recommended that the state call the new electric chair “Westinghouse.” He then dubbed the electrocution process as being “Westinghoused.”
As alternating current supplanted direct current as the source of electrical power shortly after the Columbian Exposition, the direction in the War of the Currents made an abrupt change in 1892. After his failure to win the contracts to illuminate the Columbian Exposition or to build out the Niagara project, Edison and colleagues discontinued the fear tactics and replaced them with courtroom litigation on patent infringement based on Westinghouse’s manufacture of the Edison incandescent light bulb.
As Edison General Electric began to lose its dominance in the industry, the board of directors decided on a merger with the Thomson-Houston company to stay competitive with the likes of Westinghouse. Charles A. Coffin president of Thomson – Houston, negotiated the merger with Edison General Electric. Next, the board decided to abandon direct current in favor of alternating current. This decision, in effect, terminated Edison’s leadership role at Edison General Electric. However, for his long and faithful tenure with the company, Edison was given twelve and a half percent of the stock and a pension of $600 a week.
It was during the depression of 1893 that the influence of billionaire fancier John Pierpont Morgan (J. P. Morgan) emerged as the majority stockholder of Edison General Electric. With Morgan, manipulating the board of directors of the company changed its name from Edison General Electric to General Electric. Morgan then chose Charles A. Coffin as the new president of General Electric.
|
