Thomas Alva Edison

T homas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor, scientist, and businessman who developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. He was one of the first inventors to apply the principles of mass production and large teamwork to the process of invention.

Edison is credited with numerous inventions that contributed to mass communication and, in particular, telecommunications. These included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures.

Thomas Edison was born in Milan, Ohio and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr.

Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections.

Thomas Edison began his career as an inventor in Newark, New Jersey, with the automatic repeater and his other improved telegraphic devices, but the invention which first gained him notice was the phonograph in 1877. This accomplishment was so unexpected by the public at large as to appear almost magical.

Edison did not invent the first electric light bulb, but instead invented the first commercially practical incandescent light.

After many experiments with platinum and other metal filaments, Edison returned to a carbon filament. The first successful test was on October 22, 1879.

Edison is credited with designing and producing the first commercially available fluoroscope, a machine that uses X-rays to take radiographs. Until Edison discovered that calcium tungstate fluoroscopy screens produced brighter images than the barium platinocyanide screens originally used by Wilhelm Röntgen, the technology was capable of producing only very faint images. The fundamental design of Edison’s fluoroscope is still in use today, despite the fact that Edison himself abandoned the project after nearly losing his own eyesight and seriously injuring his assistant, Clarence Dally.

The key to Edison’s fortunes was telegraphy. With knowledge gained from years of working as a telegraph operator, he learned the basics of electricity. This allowed him to make his early fortune with the stock ticker, the first electricity-based broadcast system. Edison patented the sound recording and reproducing phonograph in 1878.

Nikola Tesla

N ikola Tesla (10 July 1856 – 7 January 1943) was an inventor, mechanical engineer, and electrical engineer. He is best known for his many revolutionary developments in the field of electromagnetism in the late 19th and early 20th centuries. Tesla’s patents and theoretical work formed the basis of modern alternating current (AC) electric power systems, including the polyphase system of electrical distribution and the AC motor.

Tesla was born in the village of Smiljan and later became an American citizen. Because of his demonstration of wireless communication through radio he was widely respected as one of the greatest electrical engineers who worked in America. He pioneered modern electrical engineering and many of his discoveries were of groundbreaking importance. In the United States during this time, Tesla’s fame rivaled that of any other inventor or scientist in history or popular culture. Tesla demonstrated wireless energy transfer to power electronic devices as early as 1893, and aspired to intercontinental wireless transmission of industrial power in his unfinished Wardenclyffe Tower project.

In addition to his work on electromagnetism and electromechanical engineering, Tesla contributed in varying degrees to the establishment of robotics, remote control, radar, and computer science, and to the expansion of ballistics, nuclear physics, and theoretical physics.

Tesla engaged in reading many works, memorizing complete books, supposedly having a photographic memory.

In 1886, Tesla formed his own company, Tesla Electric Light & Manufacturing. In 1887, he constructed the initial brushless alternating current induction motor,later he developed the principles of his Tesla coil. In April 1887, Tesla began investigating what would later be called X-rays using his own single terminal vacuum tubes. This device differed from other early X-ray tubes in that it had no target electrode. We now know that this device operated by emitting electrons from the single electrode through a combination of field electron emission and thermionic emission. Once liberated, electrons are strongly repelled by the high electric field near the electrode during negative voltage peaks from the oscillating HV output of the Tesla Coil, generating X rays as they collide with the glass envelope.

Tesla demonstrated wireless energy transmission as early as 1891. The Tesla effect is a term for an application of this type of electrical conduction (that is, the movement of energy through space and matter, not just the production of voltage across a conductor).

When Tesla was 36 years old, the first patents concerning the polyphase power system were granted. He continued research of the system and rotating magnetic field principles. From 1893 to 1895, he investigated high frequency alternating currents. He generated AC of one million volts using a conical Tesla coil and investigated the skin effect in conductors, designed tuned circuits, invented a machine for inducing sleep, cordless gas discharge lamps, and transmitted electromagnetic energy without wires, building the first radio transmitter. He described and demonstrated in detail its principles.

Tesla also explained the principles of the rotating magnetic field and induction motor by demonstrating how to make an egg made of copper stand on end in his demonstration of the device he constructed known as the ‘Egg of Columbus‘.

The Tesla generator was developed by Tesla in 1895, in conjunction with his developments concerning the liquefaction of air. Tesla knew, from Lord Kelvin’s discoveries, that more heat is absorbed by liquefied air when it is re-gasified and used to drive something, than is required by theory; in other words, that the liquefaction process is somewhat anomalous or ‘over unity’.

A ‘world system’ for ‘the transmission of electrical energy without wires’ that depends upon the electrical conductivity of the earth was proposed, in which transmission in various natural media with current that passes between the two points are used to power devices. In a practical wireless energy transmission system using this principle, a high-power ultraviolet beam might be used to form a vertical ionized channel in the air directly above the transmitter-receiver stations. The same concept is used in virtual lightning rods, the electrolaser electroshock weapon, and has been proposed for disabling vehicles.

At his lab, Tesla proved that the earth was a conductor, and he produced artificial lightning (with discharges consisting of millions of volts, and up to 135 feet long). Tesla also investigated atmospheric electricity, observing lightning signals via his receivers.

Tesla worked on plans for a directed-energy weapon from the early 1900s until his death. In 1937, Tesla wrote a treatise entitled ‘The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media’, which concerned charged particle beams. Tesla published the document in an attempt to expound on the technical description of a ‘superweapon‘ that would put an end to all war. It describes an open-ended vacuum tube with a gas jet seal that allows particles to exit, a method of charging particles to millions of volts, and a method of creating and directing nondispersive particle streams.

Tesla was fluent in eight languages. Along with Serbian, he spoke Czech, English, French, German, Hungarian, Italian, and Latin.