NationMaster - Encyclopedia: Tesla coil

A Tesla coil (also teslacoil) is a type of resonant transformer, named after its inventor, Nikola Tesla. Tesla coils consist of two, or sometimes three, coupled resonant electric circuits. Tesla experimented with a large variety of coils and configurations, so it is difficult to define a "Tesla" as one specific mode of construction. Tesla used these coils to conduct innovative experiments in electrical lighting, fluorescence, x-rays, high frequency alternating current phenomena, electrotherapy, and wireless power for electric power transmission. The designs of his "early coils" and "later coils" were considerably different. Image File history File links Download high resolution version (1600x1067, 207 KB) Lightning simulator - Questacon, Canberra File links The following pages link to this file: Tesla coil Questacon â€” the National Science and Technology Centre ... Image File history File links Download high resolution version (1600x1067, 207 KB) Lightning simulator - Questacon, Canberra File links The following pages link to this file: Tesla coil Questacon â€” the National Science and Technology Centre ... Questacon â€“ the National Science and Technology Centre, is located on the southern shore of Lake Burley Griffin in Canberra, Australia. ... For other uses, see Transformer (disambiguation). ... Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... In an electrical circuit, resonance occurs at a particular frequency when the inductive reactance and the capacitive reactance are of equal magnitude, causing electrical energy to oscillate between the magnetic field of the inductor and the electric field of the capacitor. ... Not to be confused with lightning. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... City lights viewed in a motion blurred exposure. ... Electrotherapy is the use of electrical energy in the treatment of impairments of health and a conditions of abnormal functioning. ... Wireless energy transfer is the transfer of electromagnetic energy for power to do work via conduction, induction, or transmission without a physical connection. ... Power line redirects here. ...

Tesla's early and later designs usually employed a high voltage power source, one or more high voltage capacitor(s), and a spark gap to excite the primary side of the Tesla Coil with periodic bursts of high frequency current. An important characteristic of his later, higher power coil designs was that the primary and secondary circuits were also tuned so that they resonated at the same (high) frequency (typically, but not always, between 25 kHz and 2 MHz). The later Tesla coil designs can also be used to create long electrical discharges. Today they are built by many high-voltage enthusiasts. In electrical engineering High voltage refers to a voltage which is high. ... See Capacitor (component) for a discussion of specific types. ... A spark plug. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ... The term electrical breakdown has several similar but distinctly different meanings. ...

History

Tesla's early coils

The Serbian Electrician gives a description of an early tesla coil wherein a glass battery jar, six by eight inches, is wound with 60 to 80 turns of AWG No. 18 B & S magnet wire. Into this is slipped a primary consisting of eight to ten turns of AWG No. 6 B & S wire, and the whole combination immersed in a vessel containing linseed or mineral oil. (Norrie, pg. 34–35) This article is about the material. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, â€³ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... American wire gauge (AWG), also known as the Brown and Sharpe wire gauge, is used in the United States and other countries as a standard method of denoting wire diameter, especially for nonferrous, electrically conducting wire. ... Magnet wire is a copper or aluminum wire covered with thin insulation. ... Flax oil (in bottles) and coconut oil (in jars in the middle) Linseed oil, also known as flax seed oil, is a yellowish drying oil derived from the dried ripe seeds of the flax plant (Linum usitatissimum, Linaceae). ... Mineral oil or liquid petrolatum is a by-product in the distillation of petroleum to produce gasoline. ...

Disruptive "Tesla" coils

In the spring of 1891, Tesla gave demonstrations with various machines before the American Institute of Electrical Engineers at Columbia College. Following the initial research of voltage and frequency by William Crookes, Tesla designed and constructed a series of coils that produced high-voltage, high-frequency currents. These early coils used a disruptive discharge across a spark gap in their operation. The setup can be duplicated by a Ruhmkorff coil, two condensers (now called capacitors), and a second, specially constructed, disruptive coil. (Norrie, pg. 228) Image File history File links EarlyTeslaCoil. ... Image File history File links EarlyTeslaCoil. ... Josephson junction array chip developed by NIST as a standard volt. ... For other uses, see Frequency (disambiguation). ... Sir William Crookes, OM, FRS (17 June 1832 â€“ 4 April 1919) was an English chemist and physicist. ... Josephson junction array chip developed by NIST as a standard volt. ... A Disruptive discharge is the result of a dielectric being stressed beyond its dielectric strength. ... The term induction coil (archaicly known as the Ruhmkorff coil) refers to a passive electrical device used to produce high voltage pulses from a low voltage DC supply. ...

The Ruhmkorff coil, being fed from a main source, is wired to capacitors on both ends in series. A spark gap is placed in parallel to the Ruhmkorff coil before the capacitors. The discharge tips were usually metal balls under one inch in diameter, though Tesla used various forms of dischargers. The capacitors were of a special design, small with high insulation. These capacitors consisted of plates in oil that were movable. The smaller the plates, the more frequent the discharge of this early coil apparatus. The plates also help nullify the high self inductance of the secondary coil by adding capacity to it. Mica plates were placed in the spark gap to establish an air current jet to go up through the gap. This helped to extinguish the arc, making the discharge more abrupt. An air blast was also used for this objective. (Norrie, pg. 230–231) Type F mains power plug & socket The term mains usually refers to the general purpose alternating current (AC) electrical power supply (as in â€œIve connected the appliance to the mainsâ€). The term is not usually used in the United States and Canada. ... DIAMETER is a computer networking protocol for AAA (Authentication, Authorization and Accounting). ... A discharger is part of an electronic device that releases stored energy or electric charge from a battery or other source. ... Plate has several meanings: A plate electrode in a vacuum tube. ... Pneumatics is the use of pressurized air to effect mechanical motion. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current...

The capacitors are connected to a double primary (each coil in series with a capacitor). These are part of the second specially constructed disruptive coil. The primaries each have twenty turns of No. 16 B & S rubber covered wire and are wound separately on rubber tubes not less than a 1/8th inch thick. The secondary has three hundred turns of No. 30 B & S silk-covered magnet wire, wound on rubber tube or rod, and the ends encased in glass or rubber tubes. The primaries must be large enough to be loose when the secondary coil is placed between the coils. The primaries must cover around two inches of the secondary. A hard rubber division must be placed between these primary coils. The ends of the primaries not connected with the capacitors are led to a spark gap. (Norrie, pg. 35–36) This does not cite any references or sources. ... Look up Tube in Wiktionary, the free dictionary. ... Magnet wire is a copper or aluminum wire covered with thin insulation. ...

In U.S. Patent 0,454,622 , System of Electric Lighting (1891 June 23), Tesla described this early disruptive coil. It was devised for the purpose of converting and supplying electrical energy in a form suited for the production of certain novel electrical phenomena, which require currents of higher frequency and potential. It also specified an energy storage capacitor and discharger mechanism on the primary side of a radio-frequency transformer. This is the first-ever disclosure of a practical RF power supply capable of exciting an antenna to emit powerful electromagnetic radiation. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Another early Tesla coil was protected in 1897 by U.S. Patent 0,593,138 , "Electrical Transformer". This transformer developed (or converted) currents of high potential and was composed of a primary and secondary coil (optionally, one terminal of the secondary could be electrically connected with the primary; similar to modern ignition coils). This Tesla coil had the secondary being inside of, and surrounded by, the convolutions of the primary coil. This Tesla coil consisted of a primary and secondary wound in the form of a flat spiral. One coil, the secondary in step-up transformation, of the device consisted of a longer fine-wire. The apparatus was also connected to the Earth when the coil was in use. An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...

Tesla's later coils

Tesla, in U.S. Patent 0,645,576 System of Transmission of Electrical Energy and U.S. Patent 0,649,621 Apparatus for Transmission of Electrical Energy, described new and useful combinations of transformer coils. The transmitting coil or conductor arranged and excited to cause currents or oscillation to propagate through conduction through the natural medium from one point to another remote point therefrom and a receiver coil or conductor of the transmitted signals. ^[1] The production of currents of very high potential could be attained in these coils. He would later attain U.S. Patent 0,723,188 , Method of Signaling, and U.S. Patent 0,725,605 , System of Signaling, for coils with elevated transmitter capacitance with an Earth electrode. Image File history File links Wikitext. ... Image File history File links Download high resolution version (273x908, 4 KB)See also Image:TeslaCoil0645576. ... Image File history File links Download high resolution version (273x908, 4 KB)See also Image:TeslaCoil0645576. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Some of Tesla's later coils were considerably larger and operated at much higher power levels. When Tesla patented a later device in U.S. Patent 1,119,732 (Apparatus for Transmitting Electrical Energy), he called the device a high-voltage, air-core, self-regenerative resonant transformer that generates very high voltages at high frequency. However, this phrase is no longer in conventional use. Tesla's later systems were usually powered from large high voltage power transformers, used banks of glass bottle capacitors immersed in oil (to reduce corona losses), and used rotating spark gaps to handle the higher power levels. A rotating spark gap combines the ventilator needed to cool a fixed spark gap and the spark gap into a single device. The synchronous version uses a very simple electric motor, that is a permanent magnet encompassing a coil driven by the line voltage. But it needs to be started like the propeller of a biplane. It reduces spark gap losses, because it uses only two gaps, and it allows to extinguish the spark on zero passage. Tesla also dispensed with using oil to insulate his transformer coils, relying instead on the insulating properties of air. Tesla coils achieve great gain in voltage by loosely coupling two resonant LC circuits, using an air-core (ironless) transformer. Although modern Tesla Coils are usually designed to generate long sparks, Tesla's original systems were designed for wireless communication. Tesla used top terminals (toploads) having large radii of curvature to prevent losses from corona and sparks (often called streamers). The voltage gain of the circuit with a free, or an elevated, toroid is proportional to the quantity of charge displaced, which is determined by the product of the capacitance of the circuit, the voltage (which Tesla called "pressure"), and the frequency of the currents employed. Josephson junction array chip developed by NIST as a standard volt. ... The regenerative circuit (or self-regenerative circuit) allows a signal to be amplified many times by the same vacuum tube or other active component such as a field effect transistor. ... For other uses, see Transformer (disambiguation). ... In electrical engineering High voltage refers to a voltage which is high. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured. ... In electronics, gain is usually taken as the mean ratio of the signal output of a system to the signal input of the system. ... This article is about resonance in physics. ... An LC circuit consists of an inductor, represented by the letter L, and a capacitor, represented by the letter C. When connected together, an electrical current can alternate between them at an angular frequency of where L is the inductance in henries, and C is the capacitance in farads. ... It has been suggested that this article or section be merged with Wireless. ... A toroid is a doughnut-shaped object whose surface is a torus. ... Josephson junction array chip developed by NIST as a standard volt. ... This article is about pressure in the physical sciences. ...

A Tesla Coil transformer operates in a significantly different fashion than a conventional (i.e., iron core) transformer. In a conventional transformer, the windings are very tightly coupled, and voltage gain is limited to the ratio of the numbers of turns in the windings. However, the voltage gain of a disruptive Tesla Coil can be significantly greater, since it is instead proportional to the square root of the ratio of secondary and primary inductances. The coil transfers energy from one oscillating resonant circuit (the primary) to the other (the secondary) over a number of RF cycles. As the primary energy transfers to the secondary, the secondary's output voltage increases until all of the available primary energy has been transferred to the secondary (less losses). Even with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit. In mathematics, a square root of a number x is a number r such that , or in words, a number r whose square (the result of multiplying the number by itself) is x. ... An electric current i flowing around a circuit produces a magnetic field and hence a magnetic flux Î¦ through the circuit. ... An electronic circuit is an electrical circuit that also contains active electronic devices such as transistors or vacuum tubes. ...

Modern high voltage enthusiasts usually build Tesla coils that are similar to some of Tesla's "later" air core designs. These typically consist of a primary tank circuit, which is a series LC (inductance-capacitance) circuit composed of a high voltage capacitor, spark gap, and primary coil; and the secondary LC circuit, a series resonant circuit consisting of the secondary coil and the toroid. In Tesla's original plans, the secondary LC circuit is composed of a loaded secondary coil which is then placed in series with a large helical coil. The helical coil was then connected to the toroid. Most modern coils use only a single secondary coil. The toroid actually forms one terminal of a capacitor, the other terminal being the Earth (or "ground"). The primary LC circuit is "tuned" so that it will resonate at the same frequency as the secondary LC circuit. The primary and secondary coils are magnetically coupled, creating a dual-tuned resonant air-core transformer. However, unlike a conventional transformer, which may couple 97%+ of the magnetic fields between windings, a Tesla Coil's windings are "loosely" coupled, with the primary and secondary typically sharing only 10–20% of their respective magnetic fields. Earlier oil insulated Tesla Coils needed large and long insulations at their connections to prevent discharge in air. Later version Tesla Coils spread their electric fields over large distances to prevent high electrical stresses in the first place, thereby allowing operation in free air. Image File history File linksMetadata Download high resolution version (1942x1612, 384 KB) Summary Electric discharge showing the lightning-like plasma filaments from a Tesla coil. ... Image File history File linksMetadata Download high resolution version (1942x1612, 384 KB) Summary Electric discharge showing the lightning-like plasma filaments from a Tesla coil. ... a localised surplus of electrons migrates from the negative pole to the positive pole to overcome its unfavourable energetic condition. ... Not to be confused with lighting. ... For other uses, see Plasma. ... Categories: Technology stubs ... An electric current i flowing around a circuit produces a magnetic field and hence a magnetic flux Î¦ through the circuit. ... Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. ... See Capacitor (component) for a discussion of specific types. ... A spark plug. ... The Transformers toys, and the related comics and animated television series which have run from the 1980s onwards. ... The Transformers toys, and the related comics and animated television series which have run from the 1980s onwards. ... See Capacitor (component) for a discussion of specific types. ... The word ground has several meanings: The surface of the Earth Soil, a mixture of sand and organic material present on the surface of the Earth Ground (electricity), in electrical engineering, something that is connected to the Earth or at the voltage defined as zero (in the US, called ground... This article is about resonance in physics. ... The Transformers toys, and the related comics and animated television series which have run from the 1980s onwards. ... The Transformers toys, and the related comics and animated television series which have run from the 1980s onwards. ...

Tesla's original design for his largest coil used a top terminal consisting of a metallic frame in the shape of a toroid, covered with smooth half circular metal plates (constituting a very large conducting surface). On his largest system, Tesla employed on this type of shaped element within a dome. The top terminal has relatively small capacitance, charged to as high a voltage as practicable.^[2] The outer surface of the elevated conductor is where the electrical charge chiefly accumulates. It has a large radius of curvature, or is composed of separate elements which, irrespective of their own radii of curvature, are arranged close to each other so that the outside ideal surface enveloping them has a large radius.^[3] This design allowed the terminal to support very high voltages without generating corona or sparks. Tesla during his patent application process described a variety of resonator terminals at the top of this later coil.^[4] Most Modern Tesla coils use simple toroids, typically fabricated from spun metal or flexible aluminum ducting, to control the high electrical field near the top of the secondary and to direct spark outward, and away, from the primary and secondary windings. A toroid is a doughnut-shaped object whose surface is a torus. ... This article is about metallic materials. ... Wardenclyffe Tower located in Shoreham], Long Island, New York. ... For other uses, see Dome (disambiguation). ... In science and engineering, conductors, such as copper or aluminum, are materials with atoms having loosely held valence electrons. ... This article is about an authentication, authorization, and accounting protocol. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ...

Some of Tesla's work involved a more tightly coupled, air core, high frequency transformer, the output of which then fed another resonator, sometimes called an "extra coil", or simply an "upper secondary". The principle is that energy accumulates in the resonating, upper coil, and the role of transformer secondary is played by the separate, "lower" secondary; the roles are not shared by a single secondary. Modern three-coil Magnifying transmitter systems often either placed the upper secondary some distance from the transformer, or wound it on a considerably smaller diameter coil form. Direct magnetic coupling to the upper secondary was not desirable, since the third coil was designed to be driven directly by injecting RF current directly into the bottom end of the winding. A publicity photo of Tesla sitting in the Colorado Springs experimental station with his Magnifying Transmitter. The arcs are about 22 feet (7 m) long. ...

This particular Tesla circuit consists of a coil in close inductive relation with a primary, and one end of which is connected to a ground-plate, while its other end is led through a separate self-induction coil (whose connection should always be made at, or near, the geometrical center of that coil's circular aspect, in order to secure a symmetrical distribution of the current), and of a metallic cylinder carrying the current to the terminal. The primary coil may be excited by any desired source of high frequency current. The important requirement is that the primary and secondary sides must be tuned to the same resonant frequency to allow efficient transfer of energy between the primary and secondary resonant circuits. The conductor of the shaft to the terminal (topload) is in the form of a cylinder with smooth surface of a radius much larger than that of the spherical metal plates, and widens out at the bottom into a hood (which is slotted to avoid loss by eddy currents and for safety). The secondary coil is wound on a drum of insulating material, with its turns close together. When the effect of the small radius of curvature of the wire itself is overcome, the lower secondary coil behaves as a conductor of large radius of curvature, corresponding to that of the drum (this effect is applicable elsewhere). The lower end of the upper secondary coil, if desired, may be extended up to the terminal{U.S. Patent 1,119,732} and should be somewhat below the uppermost turn of the primary coil. This lessens the tendency of the charge to break out from the wire connecting both and to pass along the support. Sphere symmetry group o. ... As the circular plate moves down through a small region of constant magnetic field directed into the page, eddy currents are induced in the plate. ...

Modern day transistor or vacuum tube Tesla coils do not use a spark gap. Instead, the transistor(s) or vacuum tube(s) provide the switching or amplifying function necessary to generate RF power for the primary circuit. Transistor Tesla coils use the lowest primary operating voltage, typically between 175 to 800 volts, and drive the primary winding using either a half-bridge or full-bridge arrangement of bipolar transistors, MOSFETs or IGBTs to switch the primary current. Vacuum tube coils typically operate with plate voltages between 1500 and 6000 volts, while most spark gap coils operate with primary voltages of 6,000 to 25,000 volts. The primary winding of a traditional transistor Tesla coil is wound around only the bottom portion of the secondary (sometimes called the resonator). This helps to illustrate operation of the secondary as a pumped resonator. The primary induces alternating voltage into the bottommost portion of the secondary, providing regular "pushes" (similar to provided properly timed pushes to a playground swing). Additional energy is transferred from the primary to the secondary inductance and topload capacitance during each "push", and secondary output voltage builds (called ring-up). An electronic feedback circuit is usually used to adaptively synchronize the primary oscillator to the growing resonance in the secondary, and this is the only tuning consideration beyond the initial choice of a reasonable topload. Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. ... The metalâ€“oxideâ€“semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is by far the most common field-effect transistor in both digital and analog circuits. ... The Insulated Gate Bipolar Transistor combines the simple gate drive characteristics of the MOSFET with the high current and low saturation voltage capability of bipolar transistors by combining an isolated gate FET for the control input, and a bipolar power transistor as a switch, in a single device. ... A resonator is a device or part that vibrates (or oscillates) with waves. ... For the superhero, see Feedback (Dark Horse Comics). ... Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ...

In a Doubly Resonant Solid State Tesla Coil (DRSSTC), the electronic switching of the SSTC is combined with the resonant primary circuit of a spark-gap Tesla coil. The resonant primary circuit is formed by connecting a capacitor in series with the primary winding of the coil, so that the combination forms a series tank circuit with a resonant frequency near that of the secondary circuit. Because of the additional resonant circuit, one manual and one adaptive tuning adjustment are necessary. Also, an interrupter is usually used to reduce the duty cycle of the switching bridge, in order to improve peak power capabilities; similarly, IGBTs are more popular in this application than bipolar transistors or MOSFETs, due to their superior power handling characteristics. Performance of a DRSSTC can be comparable to a medium power spark gap Tesla coil, and efficiency (as measured by spark length versus input power) can be significantly greater than a spark gap Tesla Coil operating at the same input power. An LC circuit consists of an inductor, represented by the letter L, and a capacitor, represented by the letter C. When connected together, an electrical current can alternate between them at an angular frequency of where L is the inductance in henries, and C is the capacitance in farads. ...

Although even the relatively low primary circuit voltage of transistor Tesla Coils can be quite dangerous, all known fatalities (one hobbyist, one bystander, and one child) have, thus far, been from spark gap driven coils.

Utilization and production

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Transmission

A large Tesla coil of more modern design often operates at very high peak power levels, up to many megawatts (a million watts^[5]). It should therefore be adjusted and operated carefully, not only for efficiency and economy, but also for safety. If, due to improper tuning, the maximum voltage point occurs below the terminal, along the secondary coil, a discharge (spark) may break out and damage or destroy the coil wire, supports, or nearby objects. For other uses, see Watt (disambiguation). ... Look up Spark in Wiktionary, the free dictionary. ...

Tesla experimented with these, and many other, circuit configurations (see right). The Tesla Coil primary winding, spark gap and tank capacitor are connected in series. In each circuit, the AC supply transformer charges the tank capacitor until its voltage is sufficient to break down the spark gap. The gap suddenly fires, allowing the charged tank capacitor to discharge into the primary winding. Once the gap fires, the electrical behavior of either circuit is identical. Experiments have shown that neither circuit offers any marked performance advantage over the other.

However, in the typical circuit (above), the spark gap's short circuiting action prevents high frequency oscillations from 'backing up' into the supply transformer. In the alternate circuit, high amplitude high frequency oscillations that appear across the capacitor also are applied to the supply transformer's winding. This can induce corona discharges between turns that weaken and eventually destroy the transformer's insulation. Experienced Tesla coil builders almost exclusively use the top circuit, often augmenting it with low pass filters (resistor and capacitor (RC) networks) between the supply transformer and spark gap to help protect the supply transformer. This is especially important when using transformers with fragile high voltage windings, such as Neon-sign transformers (NSTs). Regardless of which configuration is used, the HV transformer must be of a type that self-limits its secondary current by means of internal leakage inductance. A normal (low leakage inductance) high voltage transformer must use an external limiter (sometimes called a ballast) to limit current. NSTs are designed to have high leakage inductance to limit their short circuit current to a safe level. Neon signs are often used to advertise for hotels, bars and entertainment venues. ... Leakage inductance is that property of an electrical transformer that causes a winding to appear to have some pure inductance in series with the mutually-coupled transformer windings. ...

Tuning precautions

The primary coil's resonant frequency should be tuned to the same value of the secondary coil's, using low-power oscillations, then increasing the power until the apparatus has been brought under control. While tuning, a small projection (called a "breakout bump") is often added to the top terminal in order to stimulate corona and spark discharges (sometimes called streamers) into the surrounding air. Tuning can then be adjusted so as to achieve the longest streamers at a given power level, corresponding to a frequency match between the primary and secondary coil. Capacitive 'loading' by the streamers tends to lower the resonant frequency of a Tesla Coil operating under full power. For a variety of technical reasons, toroids provide one of the most effective shapes for the top terminals of Tesla coils. This article is about the astronomical term. ...

Since Tesla coils can produce currents or discharges of very high frequency and voltage, they are useful for various purposes including classroom demonstrations, theater and movie special-effects, and product/technology safety testing.

Air discharges

While generating discharges, electrical energy from the secondary and toroid is transferred to the surrounding air as electrical charge, heat, light, and sound. The electric currents that flow through these discharges are actually due to the rapid shifting of quantities of charge from one place (the top terminal) to other places (nearby regions of air). The process is similar to charging or discharging a capacitor. The current that arises from shifting charges within a capacitor is called a displacement current. Tesla Coil discharges are formed as a result of displacement currents as pulses of electrical charge are rapidly transferred between the high voltage toroid and nearby regions within the air (called space charge regions). Although the space charge regions around the toroid are invisible, they play a profound role in the appearance and location of Tesla Coil discharges. This is a picture of a small tesla coil I made in operation. ... This is a picture of a small tesla coil I made in operation. ... This article is about the SI unit of frequency. ... The practice in electronic circuits of imposing an upper limit on the current that may be delivered to a load with the purpose of protecting the circuit generating the current from harmful effects due to a short-circuit or similar problem in the load. ... See Capacitor (component) for a discussion of specific types. ... Displacement current is a quantity related to changing electric field. ... Space charge is the electrical current that results when a metal object is heated to incandescence in a vacuum. ...

When the spark gap fires, the charged capacitor discharges into the primary winding, causing the primary circuit to oscillate. The oscillating primary current creates a magnetic field that couples to the secondary winding, transferring energy into the secondary side of the transformer and causing it to oscillate with the toroid capacitance. The energy transfer occurs over a number of cycles, and most of the energy that was originally in the primary side is transferred into the secondary side. The greater the magnetic coupling between windings, the shorter the time required to complete the energy transfer. As energy builds within the oscillating secondary circuit, the amplitude of the toroid's RF voltage rapidly increases, and the air surrounding toroid begins to undergo dielectric breakdown, forming a corona discharge. The term electrical breakdown has several similar but distinctly different meanings. ... In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured. ...

As the secondary coil's energy (and output voltage) continue to increase, larger pulses of displacement current further ionize and heat the air at the point of initial breakdown. This forms a very conductive "root" of hotter plasma, called a leader, that projects outward from the toroid. The plasma within the leader is considerably hotter than a corona discharge, and is considerably more conductive. In fact, it has properties that are similar to an electric arc. The leader tapers and branches into thousands of thinner, cooler, hairlike discharges (called streamers). The streamers look like a bluish 'haze' at the ends of the more luminous leaders, and it is the streamers that actually transfer charge between the leaders and toroid to nearby space charge regions. The displacement currents from countless streamers all feed into the leader, helping to keep it hot and electrically conductive. For other uses, see Plasma. ... A leader is a hot, highly conductive channel of plasma that plays a critical part during dielectric breakdown within in a long electrical spark. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current...

In a spark gap Tesla Coil the primary-to-secondary energy transfer process happens repetitively at typical pulsing rates of 50–500 times/second, and previously formed leader channels don't get a chance to fully cool down between pulses. So, on successive pulses, newer discharges can build upon the hot pathways left by their predecessors. This causes incremental growth of the leader from one pulse to the next, lengthening the entire discharge on each successive pulse. Repetitive pulsing causes the discharges to grow until the average energy that's available from the Tesla Coil during each pulse balances the average energy being lost in the discharges (mostly as heat). At this point, dynamic equilibrium is reached, and the discharges have reached their maximum length for the Tesla Coil's output power level. The unique combination of a rising high voltage Radio Frequency envelope and repetitive pulsing seem to be ideally suited to creating long, branching discharges that are considerably longer than would be otherwise expected by output voltage considerations alone. High voltage discharges create filamentary multi-branched discharges which are purplish blue in colour. High energy discharges create thicker discharges with fewer branches, are pale and luminous, almost white, and are much longer than low energy discharges, because of increased ionisation. There will be a strong smell of ozone and nitrogen oxides in the area. The important factors for maximum discharge length appear to be voltage, energy, and still air of low to moderate humidity. However, even more than 100 years later after the first use of Tesla Coils, there are many aspects of Tesla Coil discharges and the energy transfer process that are still not completely understood. A dynamic equilibrium occurs when two reversible processes occur at the same rate. ... It has been suggested that this article or section be merged with Radio waves. ...

Reception

Variants of Tesla coils were suggested by Tesla for receiving power from electromagnetic radiation, or alternating electric near fields, of practicable frequency, and were suggested for exploiting the vertical voltage gradient in the Earth's atmosphere. Tesla performed experiments of this type with some success, particularly in the area of receiving what was probably the near electric field of a large transmitting Tesla coil some distance away. Tesla stated that one of the seven features of this world wireless system was the construction of a "resonant receiver".^[6] The secondary of a Tesla Coil and its capacitor can be used in receive mode.^[7]^[8]^[9]^[10]^[11]^[12] Tesla himself demonstrated wireless transmission of electric power from his transmitter to his receiver. These concepts and methods are part of his wireless transmission of electric power distribution system (US1119732 — Apparatus for Transmitting Electrical Energy — 1902 January 18). Tesla made a proposal that there needed to be "thirty" such antennas worldwide.^[13] The receiving circuit of these towers are connected each with a condenser and a device adapted to open and close the receiving circuit at predetermined intervals of time.^[14] The Tesla Coil receiver has means for commutating, directing, or selecting the current impulses in the charging circuit so as to render them suitable for charging the storage device, a device for closing the receiving-circuit, and means for causing the receiver to be operated by the energy accumulated.^[15] An artists depiction of a solar satellite, which could send energy wirelessly to a space vessel or planetary surface. ... Year 1902 (MCMII) was a common year starting on Wednesday (link will display calendar) of the Gregorian calendar (or a common year starting on Tuesday [1] of the 13-day-slower Julian calendar). ... is the 18th day of the year in the Gregorian calendar. ...

A Tesla Coil used as an electrical power receiver is referred to as a Tesla Antenna.^[16]^[17]^[18]^[19] The Tesla antenna as a receiver acts as a step-down transformer with high current output.^[20] The parameters of a Tesla Coil transmitter are identically applicable to it being a receiver (e.g., an antenna circuit), due to reciprocity. Impedance, generally though, is not applied in an obvious way; for electrical impedance, the impedance at the load (e.g., where the power is consumed) is most critical and, for a Tesla Coil receiver, this is at the point of utilization (such as at an induction motor) rather than at the receiving node. Complex impedance of an antenna is related to the electrical length of the antenna at the wavelength in use. Commonly, impedance is adjusted at the load with a tuner or a matching networks composed of inductors and capacitors. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The word receiver has a number of different meanings: In communications and information processing, a receiver is the recipient (observer) of a message (information), which is sent from a source (object). ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... In classical electromagnetism, reciprocity refers to a variety of related theorems involving the interchange of time-harmonic electric current densities (sources) and the resulting electromagnetic fields in Maxwells equations for time-invariant linear media (under certain constraints). ... Electrical impedance, or simply impedance, is a measure of opposition to a sinusoidal alternating electric current. ... If an electric circuit has a well-defined output terminal, the circuit connected to this terminal (or its input impedance) is the load. ... In mathematics, a complex number is a number which is often formally defined to consist of an ordered pair of real numbers , often written: In mathematics, the adjective complex means that the underlying number field is complex numbers, for example complex analysis, complex matrix, complex polynomial and complex Lie algebra. ... In telecommunication, the term electrical length has the following meanings: 1. ... An inductor is a passive electrical device employed in electrical circuits for its property of inductance. ... See Capacitor (component) for a discussion of specific types. ...

A Tesla Coil can receive electromagnetic impulses^[21] from atmospheric electricity^[22]^[23]^[24] and radiant energy,^[25]^[26] besides normal wireless transmissions. Radiant energy throws off with great velocity minute particles which are strongly electrified and other rays falling on the insulated-conductor connected to a condenser (i.e., a capacitor) can cause the condenser to indefinitely charge electrically.^[27] The helical resonator can be "shock excited" due to radiant energy disturbances not only at the fundamental wave at one-quarter wave-length but also is excited at its harmonics. Hertzian methods can be used to excite the Tesla Antenna with limitations that result in great disadvantages for utilization, though.^[28] The methods of ground conduction and the various induction methods can also be used to excite the Tesla Antenna, but are again at a disadvantages for utilization.^[29] The charging-circuit can be adapted to be energized by the action of various other disturbances and effects at a distance. Arbitrary and intermittent oscillations that are propagated via conduction to the receiving resonator will charge the receiver's capacitor and utilize the potential energy to greater effect.^[30] Various radiations can be used to charge and discharge conductors, with the radiations considered electromagnetic vibrations of various wavelengths and ionizing potential.^[31] The Tesla Antenna utilizes the effects or disturbances to charge a storage device with energy from an external source (natural or man-made) and controls the charging of said device by the actions of the effects or disturbances (during succeeding intervals of time determined by means of such effects and disturbances corresponding in succession and duration of the effects and disturbances).^[32] The stored energy can also be used to operate the receiving device. The accumulated energy can, for example, operate a transformer by discharging through a primary circuit at predetermined times which, from the secondary currents, operate the receiving device.^[33] Cloud to ground Lightning in the global atmospheric electrical circuit. ... Radiant energy is the energy of electromagnetic waves. ... This article is about the shape. ... A resonator is a device or part that vibrates (or oscillates) with waves. ... Vibration and standing waves in a string, The fundamental and the first 6 overtones The fundamental tone, often referred to simply as the fundamental and abbreviated fo, is the lowest frequency in a harmonic series. ... A simple half-wave dipole antenna that a shortwave listener might build. ... In acoustics and telecommunication, the harmonic of a wave is a component frequency of the signal that is an integral multiple of the fundamental frequency. ...

While Tesla Coils can be used for these purposes, much of the public and media attention is toward the transmitting applications of the Tesla Coil since the plasma discharges are fascinating to most people. Regardless of this fact, Tesla did suggest that this variation of the Tesla coil could utilize the phantom loop effect to form a circuit to induct energy from the Earth's magnetic field and other radiant energy sources (including, but not limited to, electrostatics^[34]). With regard to Tesla's statements on the harnessing of natural phenomena to obtain electric power, he stated: A phantom loop is an electrical network that uses part of the natural environment to complete a circuit. ... The magnetosphere shields the surface of the Earth from the charged particles of the solar wind. ... Electrostatics (also known as static electricity) is the branch of physics that deals with the phenomena arising from what seem to be stationary electric charges. ...

Tesla stated that the output power from these devices, attained from Hertzian methods of charging, was low,^[35] but alternative charging means are available. Tesla receivers operated correctly acts as a step-down transformer with high current output.^[36] There are, to date, no commercial power generation entities or businesses that have utilized this technology to full effect. The power levels achieved by Tesla Coil receivers have, thus far, been a fraction of the output power of the transmitters.^{[citation needed]} Various public demonstration of such technology, by individuals, groups, colleges or universities, industrial concerns, government agencies or laboratories or other entities of various kind have been reported.^{[citation needed]}

Ignoring earth currents and other natural electromagnetic phenomena the Tesla antenna can receive, atmospheric electricity's total power of only all the sky-to-ground lightning everywhere on Earth from moment to moment has been stated at 700 megawatts.^[37] By comparison, a typical fossil fuel power plant (such as oil or gas) feeding the utility grid may have two gas turbines and a single steam turbine utilizing the heat from the discharged flue gas of the gas turbines, with each of the three turbines rated at 100 megawatts. On the load side, 700 MW is seen to correspond to two million parsimonious households averaging 350 watts of power use, contrasted with a world population of over six billion people. Fossil fuels or mineral fuels are fossil source fuels, this is, hydrocarbons found within the top layer of the earthâ€™s crust. ... Flue gas is gas that exits to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. ...

The amount of man-made electromagnetic radiation present on the surface of the Earth is known to those doing technical work on radio communication.^{[citation needed]} Radiation is monitored from ten-thousands of hertz (cycles per second) up to thirty billion hertz (wavelength one centimeter) or more, in many cases. Authorized radio transmissions and minor but unwanted emissions from equipment being designed are not greatly overshadowed by naturally occurring radio frequency energy. ^[38] This natural and unnatural 'noise' is abundant in the environment and can be received via wideband reception. In science, and especially in physics and telecommunication, noise is fluctuations in and the addition of external factors to the stream of target information (signal) being received at a detector. ... For the automotive term, see Wideband (automotive). ...

The skin effect myth

The dangers of high frequency electrical current are sometimes perceived as being less than at lower frequencies. This is often, but mistakenly, interpreted as being due to skin effect, a phenomenon that tends to inhibit alternating current from flowing inside conducting media. Although skin effect is applicable to effective electrical conductors (i.e., metals), the 'skin depth' of human flesh at typical Tesla Coil frequencies is still of the order of 60 inches or more.^{[citation needed]} (An independent analysis for a small coil yields 2.5 inches in normal saline; just as bad for practical purposes.)^{[citation needed]} This means that high frequency currents will still preferentially flow through deeper, better conducting, portions of an experimenter's body such as the circulatory and nervous systems. In reality, a human being's nervous system does not directly sense the flow of potentially dangerous electrical currents above 15–20 kHz; essentially, in order for nerves to be activated, a significant number of ions must cross their membrane before the current (and hence voltage) reverses. Since the body no longer provides a warning 'shock', novices may touch the output streamers of small Tesla Coils without feeling painful shocks. However, there is anecdotal evidence among Tesla Coil experimenters that temporary tissue damage may still occur and be observed as muscle pain, joint pain, or tingling for hours or even days afterwards. This is believed to be caused by the damaging effects of internal current flow, and is especially common with continuous wave (CW), solid state or vacuum tube type Tesla Coils. It is, however, of note that certain transformers can be used to provide alternating current with a frequency high enough so that the skin depth becomes small enough for the voltage to be safe. As this number is inversely proportional to the root of the frequency, this is fairly high; the number if appropriately in the megahertz. The skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor so that the current density near the surface of the conductor is greater than that at its core. ... City lights viewed in a motion blurred exposure. ... When an electromagnetic wave interacts with a conductive material, mobile charges within the material are made to oscillate back and forth with the same frequency as the impinging fields. ... A continuous wave (CW) is an electromagnetic wave of constant amplitude and frequency. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ...

Large Tesla Coils and magnifiers can deliver dangerous levels of high frequency current, and they can also develop significantly higher voltages (often 250,000–500,000 volts, or more). Because of the higher voltages, large systems can deliver higher energy, potentially lethal, repetitive high voltage capacitor discharges from their top terminals. Doubling the output voltage quadruples the electrostatic energy stored in a given top terminal capacitance. If an unwary experimenter accidentally places himself in path of the high voltage capacitor discharge to ground, the low current electric shock can cause involuntary spasms of major muscle groups and may induce life-threatening ventricular fibrillation and cardiac arrest. Even lower power vacuum tube or solid state Tesla Coils can deliver RF currents that are capable of causing temporary internal tissue, nerve, or joint damage through Joule heating. In addition, an RF arc can carbonize flesh, causing a painful and dangerous bone-deep RF burn that may take months to heal. Because of these risks, knowledgeable experimenters avoid contact with streamers from all but the smallest systems. Professionals usually use other means of protection such as a Faraday cage or a chain mail suit to prevent dangerous currents from entering their body.However, due to the typicaly high voltage in the transformers of Tesla coils, the current is often low enough to not be lethal, along with the fact that the power coming out of a transformer is always less than what comes in. This cuts down the danger of the secondary coil.^{[citation needed]} Sign warning of possible electric shock hazard An electric shock can occur upon contact of a humans body with any source of voltage high enough to cause sufficient current flow through the muscles or hair. ... Ventricular fibrillation (V-fib or VF) is a cardiac condition which consists of a lack of coordination of the contraction of the muscle tissue of the large chambers of the heart that eventually leads to the heart stopping altogether. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... In electronics, and in physics more broadly, Joule heating refers to the increase in temperature of a conductor as a result of resistance to an electrical current flowing through it. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current... Entrance to a Faraday room A Faraday cage or Faraday shield is an enclosure formed by conducting material, or by a mesh of such material. ... This article does not cite any references or sources. ...

The most serious dangers associated with Tesla Coil operation are associate with the primary circuit. It is the primary circuit that is capable of delivering a sufficient current at a significant voltage to stop the heart of a careless experimenter. Because these components are not the source of the trademark visual or auditory coil effects, they may easily be overlooked as the chief source of hazard. Should a high frequency arc strike the exposed primary coil while, at the same time, another arc has also been allowed to strike to a person, the ionized gas of the two arcs form a circuit that may conduct lethal, low-frequency current from the primary into the person. This is believed to have been the cause of death of a professional Tesla coil demonstrator, Henry Leroy Transtrom, in 1951. Henry Leroy Transtrom (1885-1951) was an American inventor and showman who worked with high voltage electricity. ...

Further, great care should be taken when working on the primary section of a coil. This remains true even when it has been disconnected from its power source for some time as a great deal of residual energy can remain stored in the tank capacitors. Proper designs should always include bypass resistors to bleed off stored charge from the capacitors. In addition, a safety shorting operation should be performed on each capacitor before any internal work is performed.^[39]

Instances and devices

Tesla's Colorado Springs laboratory possessed one of the largest Tesla coils ever built, known as the "Magnifying Transmitter". The Magnifying Transmitter is somewhat different from classic 2-coil Tesla coils. A Magnifier uses a 2-coil 'driver' to excite the base of a third coil ('resonator') that is located some distance from the driver. The operating principles of both systems are similar. The world's largest currently existing 2-coil Tesla coil was made by Greg Leyh. It is a 130,000 watt unit, part of a 38 foot tall sculpture. It is owned by Alan Gibbs and currently resides in a private sculpture park at Kakanui Point near Auckland, New Zealand.^[42] Image File history File links Size of this preview: 119 Ã— 597 pixelsFull resolution (155 Ã— 777 pixel, file size: 32 KB, MIME type: image/png) Originally uploaded at: http://peswiki. ... Image File history File links Size of this preview: 119 Ã— 597 pixelsFull resolution (155 Ã— 777 pixel, file size: 32 KB, MIME type: image/png) Originally uploaded at: http://peswiki. ... Image File history File links Size of this preview: 150 Ã— 599 pixelsFull resolution (155 Ã— 619 pixel, file size: 30 KB, MIME type: image/png) Originally uploaded at: http://peswiki. ... Image File history File links Size of this preview: 150 Ã— 599 pixelsFull resolution (155 Ã— 619 pixel, file size: 30 KB, MIME type: image/png) Originally uploaded at: http://peswiki. ... A publicity photo of Tesla sitting in the Colorado Springs experimental station with his Magnifying Transmitter. The arcs are about 22 feet (7 m) long. ... Greg Leyh (1962 - ???) An electrical engineer. ... Alan Gibbs is one of New Zealands wealthiest residents. ... For other uses, see Auckland (disambiguation). ...

The Tesla coil is an early predecessor (along with the induction coil) of a more modern device called a flyback transformer, which provides the voltage needed to power the cathode ray tube used in some televisions and computer monitors. The disruptive discharge coil remains in common use as the ignition coil^[43]^[44] or spark coil in the ignition system of an internal combustion engine. These two devices do not use resonance to accumulate energy, however, which is the distinguishing feature of a Tesla coil. They do use inductive "kick", the forced, abrupt decay of the magnetic field, such that a voltage is provided by the coil at its primary terminals that is much greater than the voltage that was applied to establish the magnetic field, and it is this higher voltage that is then multiplied by the transformer turns ratio. Thus, they do store energy, and a Tesla resonator stores energy. A modern, low power variant of the Tesla coil is also used to power plasma globe sculptures and similar devices. An induction coil or spark coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. ... A flyback transformer or line output transformer (LOPT) is a type of transformer used to generate the high voltage needed for driving a cathode ray tube or picture tube. It converts the input voltage, usually mains voltage in the range 120 to 240 volts, to an output voltage in the... Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT: 1. ... An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ... The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... An eight-inch diameter plasma globe Plasma lamps are novelty items which were most popular in the 1980s. ...

Scientists working with a glass vacuum line (e.g. chemists working with volatile substances in the gas phase, inside a system of glass tubes, taps and bulbs) test for the presence of tiny pin-holes in the apparatus (especially a newly blown piece of glassware) using a Tesla coil. When the system is evacuated and the discharging end of the coil moved over the glass, the discharge travels through any pin-hole immediately below it and thus illuminates the hole, indicating points that need to be annealed or re-blown before they can be used in an experiment.

Popularity

Tesla coils are very popular devices among certain electrical engineers and electronics enthusiasts. Someone who builds Tesla coils as a hobby is called a "coiler". The world's largest conical Tesla coil is on display at the Mid America Science Museum in Hot Springs, Arkansas. This coil produces 1.5 million volts of electrical energy. There are "coiling" conventions where people attend with their home-made Tesla coils and other electrical devices of interest. It should be noted that there are rather significant safety issues^[45] regarding coil assembly and operation by hobbyists (including professional engineers), which may be discovered by study of the literature far more reliably than by only attempting one's own analysis. An engineers degree is an academic degree which is intermediate in rank between a masters degree and a doctorate; it is occasionally to be encountered in the United States in technical fields. ... This article is about the engineering discipline. ... For other uses, see Safety (disambiguation). ...

Low power Tesla Coils are also sometimes used as a high voltage source for Kirlian photography.^[46] Coils are often useful as educational tools. Mag. Erwin Kohaut, a physics teacher at the Austrian high school BGRG 12 Rosasgasse in Vienna, Austria, and some students built a Tesla coil as a project. It stands in the cellar of that school. For several years a coil was on display at the St. Louis Science Center. It was located on the second floor near the Omnimax theatre, high up in a corner several feet behind a safety partition. Visitors could briefly activate the coil by depositing a small monetary donation into a box on the publicly-accessible side of the partition. A very large tesla coil, designed and built by Syd Klinge, is shown every year at the Coachella music and arts festival, in Coachella, Indio, California, USA. Kirlian photography refers to a form of contact print photography, theoretically associated with high-voltage. ... For other uses, see Vienna (disambiguation). ... The James S. McDonnell Planetarium, thin-shell and hyperboloid structure by Gyo Obata, one component of the St. ... IMAX theatre at the Melbourne Museum complex, Australia BFI London IMAX by night LHemisferic (Ciutat de les Arts i les CiÃ¨ncies) Valencia, Spain IMAX (short for Image Maximum) is a film format created by Canadas IMAX Corporation that has the capacity to display images of far greater...

Tesla coils can also be used to create music by modulating the system's effective "break rate" (i.e., the rate and duration of high power RF bursts) via a control unit. [1] Super Mario Brothers theme in stereo and harmony on two coils The video shows a performance on matching solid state coils operating at 41 kHz. The coils were built and operated by designer hobbyists Jeff Larson and Steve Ward. The device has been named the Zeusaphone, after Zeus, Greek god of lightning, and as a play on words referencing the Sousaphone; the name was proposed by Dr. Barry Gehm, of Lyon College,^[47] and adopted by Mr. Ward on June 21, 2007.^[48] A zeusaphone is a high-frequency, solid state Tesla coil, when its spark discharge is digitally modulated so as to produce musical tones. ... For other uses, see Zeus (disambiguation). ... Sousaphone player in Washington Square, New York City The sousaphone is a type of tuba often used in a marching band. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...

In fiction

Image File history File links Teslacoilredalert2. ... Image File history File links Teslacoilredalert2. ... This article needs a complete rewrite for the reasons listed on the talk page. ... Directed-energy weapon refers to a type of weapon that emits energy in a particular direction by a means other than a projectile. ... Blazing Angels 2: Secret Missions of WWII is a simulation game for PC, PS3 and for the Xbox 360 developed by Ubisoft Romania and published by Ubisoft. ... Blood is a PC game developed by Monolith Productions and distributed by GT Interactive. ... Destroy All Humans! is a video game developed by Pandemic Studios and published by THQ. It was released for the Xbox and PlayStation 2 computer entertainment systems on June 21, 2005. ... Arcanum: of Steamworks and Magick Obscura is a computer role-playing game developed in 2001 by Troika Games, and published by Sierra Entertainment. ... Return to Castle Wolfenstein (PC) is a first person shooter computer game published by Activision and originally released on November 19, 2001. ... Tremulous is a free and open source team-based first-person shooter with RTS elements that was released on March 31, 2006. ... Quake III Arena (Q3A) is a multiplayer first-person shooter released on December 2, 1999. ... World of Warcraft (commonly abbreviated as WoW) is a massive multiplayer online role-playing game (MMORPG) developed by Blizzard Entertainment and is the fourth game in the Warcraft series, excluding expansion packs and the cancelled Warcraft Adventures: Lord of the Clans. ... Dystopias logo. ... Half-Life 2 (commonly abbreviated to HL2) is a science fiction first-person shooter computer game that is the sequel to Half-Life. ... Ratchet and Clank is a popular video game for the Playstation 2 developed by Insomniac Games, creators of the Spyro series for the original Playstation. ... For the film based on the video game, see BloodRayne II: Deliverance. ... Crimson Skies logo. ... Fallout is a series of computer role-playing games produced and published by Interplay. ... The Sims: Bustin Out is the second title in The Sims console series. ... Jim Jarmusch Jim Jarmusch (born January 22, 1953 in Akron, Ohio) is a noted American independent film director. ... Coffee and Cigarettes is a 2003 independent film directed by Jim Jarmusch. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... kicks ass --clayton kicks ass hard! ... Megan Martha White (born December 10, 1974 in Grosse Pointe Farms, Michigan) is best known as the drummer and backing vocalist of Detroit rock duo The White Stripes. ... This article is about the American duo. ... Christopher Priest (born July 14, 1943 in Cheadle) is an English writer, whose notable works include Fugue for a Darkening Island (US title Darkening Island), Inverted World, The Affirmation, The Glamour, The Prestige and The Separation. ... The Prestige is a novel by British writer Christopher Priest. ... David Bowie (IPA: []) (born David Robert Jones on 1947 January 8) is an English singer, songwriter, actor, multi-instrumentalist, producer, arranger and audio engineer. ... Sealab 2021 is an American animated television series shown on Cartoon Networks adult-oriented programming block, Adult Swim. ... For Cartoon Network outside of the United States, see Cartoon Network around the world. ... Adult Swim is the name for an adult-oriented television programming network. ... Stormy Daniels Stormy Daniels (born March 17, 1979, in Baton Rouge, Louisiana), also known as simply Stormy, is an American pornographic actress and director. ... The word sparks can refer to a number of things: Sparks (band) a rock band led by Ron Mael and his brother Russell Mael Sparks (Coldplay song), a song by British band Coldplay from their debut album Parachutes. ... Sealab 2021 was an animated comedy shown on Cartoon Networks adult-oriented programming block, Adult Swim. ... Robot Chicken is an Emmy award-winning American stop motion animated television series produced by Stoopid Monkey, ShadowMachine Films, Williams Street, and Sony Pictures Digital, currently airing in the US as a part of Cartoon Networks Adult Swim line-up, in the United Kingdom and Ireland as part of... They LAUGHED at my theories at the institute! Fools! Ill destroy them all! Caucasian, male, aging, crooked teeth, messy hair, lab coat, spectacles/goggles, dramatic posing â€” one popular stereotype of mad scientist. ... Vger (Vejur in the novelization by Gene Roddenberry) is a fictional character in the Star Trek universe. ... Star Trek: The Motion Picture (Paramount Pictures, 1979; see also 1979 in film) is the first feature film based on the popular Star Trek science fiction television series and is released on Friday, December 7. ... Also: 1979 by Smashing Pumpkins. ... The illusions used in the film, television, and entertainment industries to simulate the imagined events in a story are traditionally called special effects (a. ... Douglas Trumbull (born April 8, 1942) is a film director and special effects supervisor. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ...

Related patents

Nikola Tesla with his invention, a wireless lightbulb powered by the electric field surrounding it. ... is the 217th day of the year (218th in leap years) in the Gregorian calendar. ... Year 1890 (MDCCCXC) was a common year starting on Wednesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the Julian calendar). ... is the 37th day of the year in the Gregorian calendar. ... 1894 (MDCCCXCIV) was a common year starting on Monday (see link for calendar). ... is the 306th day of the year (307th in leap years) in the Gregorian calendar. ... 1897 (MDCCCXCVII) was a common year starting on Friday (see link for calendar). ... is the 309th day of the year (310th in leap years) in the Gregorian calendar. ... Year 1901 (MCMI) was a common year starting on Tuesday (link will display calendar) of the Gregorian calendar (or a common year starting on Monday [1] of the 13-day-slower Julian calendar). ... is the 145th day of the year (146th in leap years) in the Gregorian calendar. ... Year 1934 (MCMXXXIV) was a common year starting on Monday (link will display full 1934 calendar) of the Gregorian calendar. ... is the 145th day of the year (146th in leap years) in the Gregorian calendar. ... Year 1934 (MCMXXXIV) was a common year starting on Monday (link will display full 1934 calendar) of the Gregorian calendar. ... is the 145th day of the year (146th in leap years) in the Gregorian calendar. ... Year 1934 (MCMXXXIV) was a common year starting on Monday (link will display full 1934 calendar) of the Gregorian calendar. ...

Contents

History

Tesla's early coils

Disruptive "Tesla" coils

Tesla's later coils

Utilization and production

Transmission

Tuning precautions

Air discharges

Reception

The skin effect myth

Instances and devices

Popularity

In fiction

Related patents

See also

Notes

Further reading

External links

Contents

History GA_googleFillSlot("encyclopedia_square");

Tesla's early coils

Disruptive "Tesla" coils

Tesla's later coils

Utilization and production

Transmission

Tuning precautions

Air discharges

Reception

The skin effect myth

Instances and devices

Popularity

In fiction

Related patents

See also

Notes

Further reading

External links

History