Tesla coil - Wikipedia. The Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1. Tesla coil circuits were used commercially in sparkgap radio transmitters for wireless telegraphy until the 1. Today their main use is for entertainment and educational displays, although small coils are still used today as leak detectors for high vacuum systems. The high electric field causes the air around the high voltage terminal to ionize and conduct electricity, allowing electricity to leak into the air in colorful corona discharges, brush discharges and streamer arcs. Tesla coils are used for entertainment at science museums and public events, and for special effects in movies and television. A Tesla coil is a radio frequencyoscillator that drives an air- core double- tuned resonant transformer to produce high voltages at low currents. More sophisticated designs use transistor or thyristor. Typical voltages are between 5 and 3. V). Its large surface area suppresses premature air breakdown and arc discharges, increasing the Q factor and output voltage. Resonant transformer. Unipolar Tesla coil circuit. C2 is not an actual capacitor but represents the capacitance of the secondary windings L2, plus the capacitance to ground of the toroid electrode E. A more detailed equivalent circuit of the secondary showing the contributions of various stray capacitances. The Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high-voltage, low-current, high. Wireless power transfer (WPT), wireless power transmission, wireless energy transmission, or electromagnetic power transfer is the transmission of electrical energy. MMORPG.com covers all of the latest online MMO news for the best MMORPG games and industry coverage. Gamesitestop100 gives you the best game sites on the net in many game categories. Sign up your game site now and gain free traffic. Cheatbook your source for Cheats, Video game Cheat Codes and Game Hints, Walkthroughs, FAQ, Games Trainer, Games Guides, Secrets, cheatsbook. Download the free trial version below to get started. Double-click the downloaded file to install the software. The specialized transformer used in the Tesla coil circuit, called a resonant transformer, oscillation transformer or radio- frequency (RF) transformer, functions differently from an ordinary transformer used in AC power circuits. Each winding has a capacitance across it and functions as an LC circuit (resonant circuit, tuned circuit), storing oscillating electrical energy, analogously to a tuning fork. The primary coil(L1) consisting of a relatively few turns of heavy copper wire or tubing, is connected to a capacitor(C1) through the spark gap(SG). The secondary is not connected to an actual capacitor, but it also functions as an LC circuit, the inductance of (L2) resonates with stray capacitance (C2), the sum of the stray parasitic capacitance between the windings of the coil, and the capacitance of the toroidal metal electrode attached to the high voltage terminal. The primary and secondary circuits are tuned so they resonate at the same frequency, they have the same resonant frequency. This allows them to exchange energy, so the oscillating current alternates back and forth between the primary and secondary coils. The peculiar design of the coil is dictated by the need to achieve low resistive energy losses (high Q factor) at high frequencies. However at high frequencies an iron core causes energy losses due to eddy currents and hysteresis, so it is not used in the Tesla coil. Due to the iron core and close proximity of the windings, they have a high mutual inductance(M), the coupling coefficient is close to unity 0. The primary carries very high currents. Since high frequency current mostly flows on the surface of conductors due to skin effect, it is often made of copper tubing or strip with a large surface area to reduce resistance, and its turns are spaced apart, which reduces proximity effect losses and arcing between turns. The primary is the flat red spiral winding at bottom, the secondary is the vertical cylindrical coil wound with fine red wire. The high voltage terminal is the aluminum torus at the top of the secondary coil. Bipolar coil, used in the early 2. There are two high voltage output terminals, each connected to one end of the secondary, with a spark gap between them. The primary is 1. The output circuit can have two forms: Unipolar - One end of the secondary winding is connected to a single high voltage terminal, the other end is grounded. This type is used in modern coils designed for entertainment. The primary winding is located near the bottom, low potential end of the secondary, to minimize arcs between the windings. Since the ground (Earth) serves as the return path for the high voltage, streamer arcs from the terminal tend to jump to any nearby grounded object. Bipolar - Neither end of the secondary winding is grounded, and both are brought out to high voltage terminals. The primary winding is located at the center of the secondary coil, equidistant between the two high potential terminals, to discourage arcing. Operation cycle. The circuit operates in a rapid, repeating cycle in which the supply transformer (T) charges the primary capacitor (C1) up, which then discharges in a spark through the spark gap, creating a brief pulse of oscillating current in the primary circuit which excites a high oscillating voltage across the secondary. This completes the primary circuit and current from the capacitor flows through the primary coil (L1). The current flows rapidly back and forth between the plates of the capacitor through the coil, generating radio frequency oscillating current in the primary circuit at the circuit's resonant frequency. The oscillating magnetic field of the primary winding induces an oscillating current in the secondary winding (L2), by Faraday's law of induction. Over a number of cycles, the energy in the primary circuit is transferred to the secondary. The total energy in the tuned circuits is limited to the energy originally stored in the capacitor C1, so as the oscillating voltage in the secondary increases in amplitude (. Although the ends of the secondary coil are open, it also acts as a tuned circuit due to the capacitance (C2), the sum of the parasitic capacitance between the turns of the coil plus the capacitance of the toroid electrode E. Current flows rapidly back and forth through the secondary coil between its ends. Because of the small capacitance, the oscillating voltage across the secondary coil which appears on the output terminal is much larger than the primary voltage. The secondary current creates a magnetic field that induces voltage back in the primary coil, and over a number of additional cycles the energy is transferred back to the primary. This process repeats, the energy shifting rapidly back and forth between the primary and secondary tuned circuits. The oscillating currents in the primary and secondary gradually die out (. The oscillating current in the secondary may continue for some time. The current from the supply transformer begins charging the capacitor C1 again and the cycle repeats. This entire cycle takes place very rapidly, the oscillations dying out in a time of the order of a millisecond. Each spark across the spark gap produces a pulse of damped sinusoidal high voltage at the output terminal of the coil. Each pulse dies out before the next spark occurs, so the coil generates a string of damped waves, not a continuous sinusoidal voltage. Depending on how the spark gap is set, usually one or two sparks occur at the peak of each half- cycle of the mains current, so there are more than a hundred sparks per second. Thus the spark at the spark gap appears continuous, as do the high voltage streamers from the top of the coil. The supply transformer (T) secondary winding is connected across the primary tuned circuit. It might seem that the transformer would be a leakage path for the RF current, damping the oscillations. However its large inductance gives it a very high impedance at the resonant frequency, so it acts as an open circuit to the oscillating current. If the supply transformer has inadequate leakage inductance, radio frequency chokes are placed in its secondary leads to block the RF current. Oscillation frequency. To produce the largest output voltage, the primary and secondary tuned circuits are adjusted to resonance with each other. If the two coils were separate, the resonant frequencies of the primary and secondary circuits, f. So the factor 1. Therefore, most sources.
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