INVENTIONS
X-Ray
Modern day radiologists are seldom aware of the impact Nikola Tesla had on the practical use of the x-ray. In 1894, Tesla began to notice that the photographic plates he used in his laboratory were mysteriously becoming damaged. This started his investigation on what is now known as the x-ray, which at the time was still an unknown entity. Tesla invented his own vacuum tube (an x-ray bulb) which emitted electrons from a single electrode, discovering a type of radiation that became known as braking radiation. He produced the first x-ray image using this technique and also was the first person to obtain images (he called them shadowgraphs) of the human body. Tesla was the first to point out the clinical benefits of using the x-ray. He noticed that the positions of foreign bodies and the presence of lung ailments were easy to see with his rays; denser substances were more opaque in the images. He also realized that working with the x-ray tubes could be hazardous. He assumed correctly that in order to protect oneself from ill effects of the radiation, it was important to keep at a distance from the source, wear protective shielding, and avoid too much exposure time. Tesla's contribution to the understanding of x-rays is for the most part unknown, mainly because his laboratory (which contained all of his findings) was completely destroyed by a fire in 1895.
RADIO |
Shadowgraph of a human foot in a shoe. Tesla obtained the image in 1896 with x-rays generated by his own vacuum tube at a distance of eight feet.
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Nikola Tesla had created a basic design for the radio as early as 1892. He found that he could transmit and receive powerful radio signals when they were tuned to resonate at the same frequency. In 1898, Tesla patented a radio-controlled boat. Later that year, he demonstrated the use of his boat in the Annual Electrical Exhibition in Madison Square Garden. Tesla's boat was constructed with an antenna, which transmitted the radio waves coming from the command post where Tesla was standing. Those radio waves were received by a device he called a coherer, which used the radio waves to mechanically move the propellers on the boat. Tesla could change the boat's direction with manually operated controls from his command post. This was the first practical application of radio waves and many consider it to be the birth of robotics.
Nikola Tesla's radio-controlled boat.
Alternating Current
In the late 1800's, electricity was a novelty that had just started to become available to the public. Thomas Alva Edison first unveiled his electric incandescent lamp for public use in January 1880. The Edison system used direct current electricity, otherwise known as DC. Direct current always flows in one direction and is created by DC generators, but it has its limitations. One of the most important drawbacks of DC electricity is that it is difficult to transmit economically over long distances. One of Edison's contemporaries named Elihu Thomson realized that this was a major flaw if electricity were to be used in a widespread manner by the public. He sketched a competing system of transmitting electricity called the alternating current (AC) system. It relied on high-voltage transmission lines to carry power far from where it was generated. Thomson's sketch also indicated the need for a piece of equipment to step down the voltage at the point of use. Known as a transformer, this technology would not be fully developed for commercial use until 1886. However, Tesla built upon Thomson's ideas and constructed what would become known as a polyphase induction motor. This motor was based on using multiple alternating currents (as opposed to one current) to induce out-of-phase magnetic fields which move a magnetic rotor producing mechanical motion. In 1887, Tesla filed for seven U.S. patents describing a complete AC system based on his induction motor. His system also included generators, transformers, transmission lines, and lighting. Not long after, Tesla delivered a lecture about his revolutionary new system to the American Institute of Electrical Engineers and was able to convince the public that his AC system was far superior to Edison's DC system.
TESLA COIL
The Tesla coil is one of Nikola Tesla's most famous inventions. Tesla coils are unique in the fact that they create extremely powerful electrical fields. Large coils have been known to wirelessly light up florescent bulbs up to 50 feet away, and because of the fact that it is an electric field that goes directly into the bulb, even burned-out florescent lights glow.
Tesla called his device an oscillating transformer, but the rest of the world called it the "Tesla coil." The Tesla coil consists of two wire coils: the primary and the secondary. The primary coil is connected to a high-frequency AC power source and has a capacitor in the circuit. The secondary coil, or induction coil, produces a spark. Tesla realized that he could build up higher than ever voltages in the secondary induction coil by creating "resonance" in his primary coil with very high frequency AC currents. The electrical impulses in the primary coil are spaced apart perfectly so that new electrical waves reinforce preceding waves. A current is induced in the secondary coil and discharge takes place ionizing the surrounding air creating an electrical arc. Voltages can be well above 1,000,000 volts; Tesla himself got arcs up to 100,000,000 volts. The whole process can repeat itself many thousand times per second. Using these discoveries, Tesla made antennae of the high-voltage end of the secondary coil creating a powerful radio transmitter. In the early decades of radio, most practicable radios utilized Tesla coils in their transmission antennae. Tesla himself used larger or smaller versions of his invention to investigate fluorescence, x-rays, radio waves, wireless power transmission, and even the electromagnetic nature of the earth and its atmosphere. Tesla accidentally found that the radio waves produced by his coil traveled along his skin and did not harm him internally. He used this phenomenon to entertain people by holding the terminal of the Tesla coil in one hand and a light bulb in the other. High frequency, high voltage, low amperage electricity traveled over his skin and illuminated the bulb in his other hand. |
The discharge of a Tesla Coil demonstrated in Colorado Springs Laboratory.
A modern-day Tesla Coil.
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