text:
Tesla coil
|Application in educational demonstrations, novelty lighting, music
|Nikola Tesla
|Related items
|Transformer, electromagnetic field
A Tesla coil is an electrical resonant transformer circuit invented by Nikola Tesla around 1891.[1] It is used to produce high-voltage, low-current, high frequency alternating-current electricity.[2][3][4][5][6][7][8] Tesla experimented with a number of different configurations consisting of two, or sometimes three, coupled resonant electric circuits.
Tesla used these coils to conduct innovative experiments in electrical lighting, phosphorescence, X-ray generation, high frequency alternating current phenomena, electrotherapy, and the transmission of electrical energy without wires. Tesla coil circuits were used commercially in sparkgap radio transmitters for wireless telegraphy until the 1920s,[1][9][10][11][12][13] and in medical equipment such as electrotherapy and violet ray devices. Today their main use is for entertainment and educational displays, although small coils are still used today as leak detectors for high vacuum systems.[8]
- 1 Theory
- 2 History
- 3 Modern-day Tesla coils
- 4 Practical aspects of design
- 5 Applications
- 6 High-frequency electrical safety
- 7 Related patents
- 8 See also
- 9 References
- 10 Further reading
- 11 External links
A Tesla coil is a radio frequency oscillator driving a double tuned resonant transformer.[14] The Tesla coil operates in a significantly different fashion from a conventional iron-core transformer. In a conventional transformer, the windings are very tightly coupled (i.e., in close physical proximity to one another), and voltage gain is determined by the ratio of the numbers of turns in the windings. Unlike a conventional iron core transformer, which typically couple 97%+ of the magnetic fields between windings, the windings in a Tesla coil are more widely separated and the magnetic core is eliminated. The primary and secondary are "loosely coupled", typically sharing only 10–20% of their respective magnetic fields.
In addition, the inductance of each winding is part of a tuned LC circuit. The primary winding and primary ("tank") capacitor form the primary LC circuit. The secondary LC circuit consists of the secondary winding, and the combination of its stray capacitance and self-capacitance of the top terminal to ground. The primary and secondary LC circuits are tuned so that each circuit resonates at an identical high frequency. By loosely coupling the two LC circuits, energy in an oscillating primary LC circuit can be transferred to the secondary LC circuit (or vice versa) at a rate that depends on the coupling coefficient between windings.
Energy transfer between windings is significantly more complex than for a conventional iron core transformer. The primary circuit is typically driven into oscillation by discharging a fixed amount of energy from the charged primary capacitor into the primary winding through a spark gap). However, it takes a number of RF cycles for energy in the oscillating primary LC circuit to fully transfer into the secondary LC circuit. Energy in the primary circuit decreases it is transferred into the secondary circuit, until all of the system's initial energy, less losses, now resides in the oscillating secondary circuit. The lower the coupling coefficient, the greater the number of RF cycles required to complete an energy transfer from one LC circuit to the other. If the spark gap continues to conduct, energy in the oscillating secondary now begins to transfer back into the primary circuit until all the remaining system energy once again resides in the oscillating primary LC circuit many RF cycles later. This bidirectional energy transfer process, over multiple oscillations, is common behavior (called the Transient response) for a simple coupled resonant system.
As the primary's energy transfers to the secondary, the secondary's oscillating output voltage increases ("rings up") until all of the available primary energy (that was initially stored in the primary tank capacitor) has been transferred to the secondary (less losses, mainly from the spark gap switch). 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. The voltage achievable from a Tesla coil can be significantly greater than a conventional low frequency transformer. Per Faraday's law of induction, the induced voltage per turn (or EMF) for the windings is proportional to the rate of change of magnetic flux. Operation at higher frequencies dramatically increases the volts-per-turn, and small-medium size Tesla coils typically develop EMF's of several hundreds of volts per turn.
The secondary of a Tesla coil is not simply a lumped element inductor. Its electrical behavior is considerably more complex due to the presence of distributed turn-to-turn capacitance and stray capacitance that is a function of the height of each turn above ground. It is more accurately described, using distributed modeling, as a helical resonator or a slow-wave helical resonator[15][16] Unlike a simple LC circuit which resonates at a single frequency, a helical resonator resonates at a number of frequencies. Most Tesla coils operate the resonator at the lowest, or fundamental frequency, since this mode develops the highest voltage at the top of the resonator when the bottom of the resonator is grounded. This mode is sometimes is also called quarter-wave resonance, since the electrical length of the resonator is one-fourth of the slow-wave wavelength within the resonator when it is operating at its fundamental frequency. A resonator rings at many higher frequencies (or harmonics). However, operation at a harmonic is not usually done, since one or more high voltage nodes will be formed between the top and bottom of the resonator. When used in a spark gap Tesla coil, the resonator is operated at its fundamental mode, and its behavior can be approximated as a lumped inductor in parallel with the combination of its self-capacitance and topload capacitance. Similarly, when driven from a CW source at its fundamental frequency, the resonator can be approximated as a high-Q inductor in parallel with its self-capacitance and topload capacitance.
In a spark gap switched Tesla coil, voltage gain is proportional to the square root of the ratio of secondary and primary inductances. This is a direct consequence of Conservation of energy. Since the primary and secondary are tuned to the same frequency, LC (primary circuit) = LC (secondary circuit), so the voltage gain is also proportional to the square root of the ratio of the primary tank capacitance to the combination of secondary and topload stray capacitances to ground. In a Tesla Coil driven from a continuous RF source, such as some types of vacuum tube or solid state Tesla coils, voltage gain is proportional to the Q of the secondary coil.
The original Tesla coil transformer employed a capacitor which, upon break-down of a short spark gap, became connected to a coil of a few turns (the primary winding set), forming a resonant circuit with the frequency of oscillation, usually 20–100 kHz, determined by the capacitance of the capacitor and the inductance of the coil. The capacitor was charged to the voltage necessary to rupture the air of the gap during the input line cycle, about 10 kV by a line-powered transformer connected across the gap. The line transformer was designed to have higher than normal leakage inductance to tolerate the short circuit occurring while the gap remained ionized, or for the few milliseconds until the high frequency current had died away.
The spark gap is set up so that its breakdown occurs at a voltage somewhat less than the peak output voltage of the transformer in order to maximize the voltage across the capacitor. The sudden current through the spark gap causes the primary resonant circuit to ring at its resonant frequency. The ringing primary winding magnetically couples energy into the secondary over several RF cycles, until all of the energy that was originally in the primary has been transferred to the secondary. Ideally, the gap would then stop conducting (quench), trapping all of the energy into the oscillating secondary circuit. Usually the gap reignites, and energy in the secondary transfers back to the primary circuit over several more RF cycles. Cycling of energy may repeat for several times until the spark gap finally quenches. Once the gap stops conducting, the transformer begins recharging the capacitor. Depending on the breakdown voltage of the spark gap, it may fire many times during a mains AC cycle.
A more prominent secondary winding, with vastly more turns of thinner wire than the primary, was positioned to intercept some of the magnetic field of the primary. The secondary was designed to have the same frequency of resonance as the primary using only the stray capacitance of the winding itself to ground and that of any "top hat" terminal placed at the top of the secondary. The lower end of the long secondary coil must be grounded to the surroundings.
The later and higher-power coil design has a single-layer primary and secondary. These Tesla coils are often used by hobbyists and at venues such as science museums to produce long sparks. The American Electrician[17] gives a description of an early Tesla coil wherein a glass battery jar, 15 × 20 cm (6 × 8 in) is wound with 60 to 80 turns of AWG No. 18 B & S magnet wire (0.823 mm²). Into this is slipped a primary consisting of eight to ten turns of AWG No. 6 B & S wire (13.3 mm2) and the whole combination is immersed in a vessel containing linseed or mineral oil.[18]
Magnifying transmitter[edit]
Tesla built a laboratory in Colorado Springs and between 1899-1900 performed experiments on wireless power transmission there. The Colorado Springs laboratory possessed one of the largest Tesla coils ever built, which Tesla called a "magnifying transmitter" as it was intended to transmit power to a distant receiver. With an input power of 300 kilowatts it could produce potentials in the 12 to 20 megavolt range at a frequency of 150 kHz, creating huge 140 foot "lightning" bolts. The magnifying transmitter design is somewhat different from the classic two-coil Tesla coil circuit. In addition to the primary and secondary coils it had a third "resonator" coil, not magnetically coupled to the others, attached to the top terminal of the secondary. When driven by the secondary it produced additional high voltage by resonance, being adjusted to resonate with its own parasitic capacitance at the frequency of the other coils.
The Colorado Springs apparatus consisted of a 53-foot diameter Tesla coil around the periphery of the lab, with a single-turn primary buried in the ground and a secondary of 50 turns of heavy wire on a 9 foot high circular "fence". The primary was connected to a bank of oil capacitors to make a tuned circuit, excited by a rotary spark gap at 20 - 40 kilovolts from a powerful utility transformer. The top of the secondary was connected to a 20 ft diameter "resonator" coil in the center of the room, attached to a telescoping 143 foot "antenna" with a 30-inch metal ball on top which could project through the roof of the lab.
Wardenclyffe coil[edit]
Tesla's 1902 design for his advanced magnifying transmitter used a top terminal consisting of a metal frame in the shape of a toroid, covered with hemispherical plates (constituting a very large conducting surface). The top terminal has relatively small capacitance, charged to as high a voltage as practicable.[19] The outer surface of the elevated conductor is where the electrical voltage chiefly occurs. It had a large radius of curvature, or was composed of separate elements which, irrespective of their own radii of curvature, were arranged close to each other so that the outside ideal surface enveloping them has a large radius.[20] 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.[21]
Modern-day Tesla coils[edit]
Modern high-voltage enthusiasts usually build Tesla coils similar to some of Tesla's "later" 2-coil air-core designs. These typically consist of a primary tank circuit, 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 plus a terminal capacitance or "top load". In Tesla's more advanced (magnifier) design, a third coil is added. The secondary LC circuit is composed of a tightly coupled air-core transformer secondary coil driving the bottom of a separate third coil helical resonator. Modern 2-coil systems use a single secondary coil. The top of the secondary is then connected to a topload terminal, which forms one 'plate' of a capacitor, the other 'plate' being the earth (or "ground"). The primary LC circuit is tuned so that it resonates 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. Earlier oil-insulated Tesla coils needed large and long insulators at their high-voltage terminals to prevent discharge in air. Later Tesla coils spread their electric fields over larger distances to prevent high electrical stresses in the first place, thereby allowing operation in free air. Most modern Tesla coils also use toroid-shaped output terminals. These are often fabricated from spun metal or flexible aluminum ducting. The toroidal shape helps to control the high electrical field near the top of the secondary by directing sparks outward and away from the primary and secondary windings.
A more complex version of a Tesla coil, termed a "magnifier" by Tesla, uses a more tightly coupled air-core resonance "driver" transformer (or "master oscillator") and a smaller, remotely located output coil (called the "extra coil" or simply the resonator) that has a large number of turns on a relatively small coil form. The bottom of the driver's secondary winding is connected to ground. The opposite end is connected to the bottom of the extra coil through an insulated conductor that is sometimes called the transmission line. Since the transmission line operates at relatively high RF voltages, it is typically made of 1" diameter metal tubing to reduce corona losses. Since the third coil is located some distance away from the driver, it is not magnetically coupled to it. RF energy is instead directly coupled from the output of the driver into the bottom of the third coil, causing it to "ring up" to very high voltages. The combination of the two-coil driver and third coil resonator adds another degree of freedom to the system, making tuning considerably more complex that for a 2-coil system. The transient response for multiple resonance networks (of which the Tesla magnifier is a sub-set) has only recently been solved.[23] It is now known that a variety of useful tuning "modes" are available, and in most operating modes the extra coil will ring at a different frequency than the master oscillator.[24]
Primary switching[edit]
Modern transistor or vacuum tube Tesla coils do not use a primary 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. Solid-state Tesla coils use the lowest primary operating voltage, typically between 155 to 800 volts, and drive the primary winding using either a single, 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 coil. This configuration illustrates operation of the secondary as a pumped resonator. The primary 'induces' alternating voltage into the bottom-most portion of the secondary, providing regular 'pushes' (similar to providing properly timed pushes to a playground swing). Additional energy is transferred from the primary to the secondary inductance and top-load 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 top-load.
In a dual resonant solid-state Tesla coil (DRSSTC), the electronic switching of the solid-state Tesla coil 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, 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. A current-limiting circuit is usually used to limit maximum primary tank current (which must be switched by the IGBT's) to a safe level. 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.
Practical aspects of design[edit]
High voltage production[edit]
A large Tesla coil of more modern design often operates at very high peak power levels, up to many megawatts (millions of watts[25]). It is therefore 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.
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, 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.
Tuning precautions[edit]
The primary coil's resonant frequency is tuned to that of the secondary, by using low-power oscillations, then increasing the power (and retuning if necessary) until the system operates properly at maximum power. 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. A toroidal topload is often preferred to other shapes, such as a sphere. A toroid with a major diameter that is much larger than the secondary diameter provides improved shaping of the electrical field at the topload. This provides better protection of the secondary winding (from damaging streamer strikes) than a sphere of similar diameter. And, a toroid permits fairly independent control of topload capacitance versus spark breakout voltage. A toroid's capacitance is mainly a function of its major diameter, while the spark breakout voltage is mainly a function of its minor diameter.
Air discharges[edit]
While generating discharges, electrical energy from the secondary and toroid is transferred to the surrounding air as electrical charge, heat, light, and sound. The process is similar to charging or discharging a capacitor, except that a Tesla coil uses AC instead of DC. 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.
When the spark gap fires, the charged capacitor discharges into the primary winding, causing the primary circuit to oscillate. The oscillating primary current creates an oscillating 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 to ground. Energy transfer occurs over a number of cycles, until most of the energy that was originally in the primary side is transferred to 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 the toroid begins to undergo dielectric breakdown, forming a corona discharge.
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 electrically 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, its properties are similar to an electric arc. The leader tapers and branches into thousands of thinner, cooler, hair-like discharges (called streamers). The streamers look like a bluish 'haze' at the ends of the more luminous leaders. The streamers 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.
The primary break rate of sparking Tesla coils is slow compared to the resonant frequency of the resonator-topload assembly. When the switch closes, energy is transferred from the primary LC circuit to the resonator where the voltage rings up over a short period of time up culminating in the electrical discharge. In a spark gap Tesla coil, the primary-to-secondary energy transfer process happens repetitively at typical pulsing rates of 50–500 times per second, depending on the frequency of the input line voltage. At these rates, previously-formed leader channels do not 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 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 multibranched 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. A strong smell of ozone and nitrogen oxides will occur in the area. The important factors for maximum discharge length appear to be voltage, energy, and still air of low to moderate humidity. There are comparatively few scientific studies about the initiation and growth of pulsed lower-frequency RF discharges, so some aspects of Tesla coil air discharges are not as well understood when compared to DC, power-frequency AC, HV impulse, and lightning discharges.
Tesla coil circuits were used commercially in sparkgap radio transmitters for wireless telegraphy until the 1920s,[1][9][10] and in electrotherapy and pseudomedical devices such as violet ray. Today, although small Tesla coils are used as leak detectors in scientific high vacuum systems[8] and igniters in arc welders,[26] their main use is entertainment and educational displays, Tesla coils are built by many high-voltage enthusiasts, research institutions, science museums, and independent experimenters. Although electronic circuit controllers have been developed, Tesla's original spark gap design is less expensive and has proven extremely reliable.
Tesla coils are very popular devices among certain electrical engineers and electronics enthusiasts. Builders of Tesla coils as a hobby are called "coilers". A very large Tesla coil, designed and built by Syd Klinge, is shown every year at the Coachella Valley Music and Arts Festival, in Coachella, Indio, California, USA. People attend "coiling" conventions where they display their home-made Tesla coils and other electrical devices of interest. Austin Richards, a physicist in California, created a metal Faraday Suit in 1997 that protects him from Tesla Coil discharges. In 1998, he named the character in the suit Doctor MegaVolt and has performed all over the world and at Burning Man 9 different years.
Low-power Tesla coils are also sometimes used as a high-voltage source for Kirlian photography.[27]
Tesla coils can also be used to generate sounds, including music, by modulating the system's effective "break rate" (i.e., the rate and duration of high power RF bursts) via MIDI data and a control unit. The actual MIDI data is interpreted by a microcontroller which converts the MIDI data into a PWM output which can be sent to the Tesla coil via a fiber optic interface.[28][29] The YouTube video Super Mario Brothers theme in stereo and harmony on two coils 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 idea of playing music on the singing Tesla coils flies around the world and a few followers[30] continue the work of initiators. An extensive outdoor musical concert has demonstrated using Tesla coils during the Engineering Open House (EOH) at the University of Illinois at Urbana-Champaign. The Icelandic artist Björk used a Tesla coil in her song "Thunderbolt" as the main instrument in the song. The musical group ArcAttack uses modulated Tesla coils and a man in a chain-link suit to play music.
The world's largest currently existing two-coil Tesla coil is a 130,000-watt unit, part of a 38-foot-tall (12 m) sculpture titled Electrum owned by Alan Gibbs and currently resides in a private sculpture park at Kakanui Point near Auckland, New Zealand.[31] The most powerful conical Tesla coil (1.5 million volts) was installed in 2002 at the Mid-America Science Museum in Hot Springs, Arkansas.[32] This is a replica of the Griffith Observatory conical coil installed in 1936.
Vacuum system leak detectors[edit]
Scientists working with high vacuum systems test for the presence of tiny pin holes in the apparatus (especially a newly blown piece of glassware) using high-voltage discharges produced by a small handheld Tesla coil. When the system is evacuated the high voltage electrode of the coil is played over the outside of the apparatus. The discharge travels through any pin hole immediately below it, producing a corona discharge inside the evacuated space which illuminates the hole, indicating points that need to be annealed or reblown before they can be used in an experiment.
Wireless power transmission[edit]
Tesla used his Tesla coil circuits to perform the first experiments in wireless power transmission at the turn of the 20th century,[33][34][35] In the period 1891 to 1904 he experimented with transmitting RF power between elevated metal terminals by capacitive coupling and between coils of wire by inductive coupling.[34][35][36] In demonstrations before the American Institute of Electrical Engineers[36] and at the 1893 Columbian Exposition in Chicago he lit light bulbs from across a stage.[35] He found he could increase the distance by using a receiving LC circuit tuned to resonance with the Tesla coil's LC circuit,[37] transferring energy by resonant inductive coupling.[35] At his Colorado Springs laboratory during 1899-1900, by using voltages of the order of 20 megavolts generated by his enormous magnifying transmitter coil, he was able to light three incandescent lamps at a distance of about 100 feet (30 m).[5][38] The resonant inductive coupling technique pioneered by Tesla has recently become a central concept in modern wireless power development, and is being widely used in short range wireless transmission systems[35][39] like cellphone charging pads.
The inductive and capacitive coupling used in Tesla's experiments are "near-field" effects,[35] meaning that the energy transferred decreases with the sixth power of the distance between transmitter and receiver,[35][40][41][42] so they cannot be used for long-distance transmission. However, Tesla was obsessed with developing a long range wireless power transmission system which could transmit power from power plants directly into homes and factories without wires, described in a visionary June, 1900 article in Century Magazine; "The Problem of Increasing Human Energy",[43] and he believed resonance was the key. Tesla claimed to be able to transmit power on a worldwide scale, using a method that involved conduction through the Earth and atmosphere.[44][45][46][47] Tesla was vague about his methods. One of his ideas was that transmitting and receiving terminals could be suspended in the air by balloons at 30,000 feet (9,100 m) altitude, where the air pressure is lower.[44] At this altitude, Tesla thought, an ionized layer would allow electricity to be sent at high voltages (millions of volts) over long distances.
In 1901, Tesla began construction of a high-voltage wireless power station, the Wardenclyffe Tower at Shoreham, New York. Essentially a large Tesla coil intended as a prototype transmitter for a "World Wireless System" that was to transmit both information and power worldwide, by 1904 he had lost funding and the facility was never completed.[46][48] Although Tesla seems to have believed his ideas were proven,[49] he had a history of making claims that he had not confirmed by experiment,[50][51] and there seems to be no evidence that he ever transmitted significant power beyond the short-range demonstrations above.[5][34][37][49][51][52][53][54][55] The only report of long-distance transmission by Tesla is a claim, not found in reliable sources, that in 1899 he wirelessly lit 200 light bulbs at a distance of 26 miles (42 km).[5][49] There is no independent confirmation of this supposed demonstration;[5][49][56] Tesla did not mention it,[49] and it does not appear in his laboratory notes.[56][57] It originated in 1944 from Tesla's first biographer, John J. O'Neill,[5] who said he pieced it together from "fragmentary material... in a number of publications".[58] In the 110 years since Tesla's experiments, efforts by others to achieve long distance power transmission using Tesla coils have failed,[5][35][49][54] and the scientific consensus is his World Wireless system would not have worked.[13][33][34][37][46][49][52][59][60] Contemporary scientists point out that while Tesla's coils function as radio transmitters, transmitting energy in the form of radio waves, the frequency he used, around 150 kHz, is far too low for practical long range power transmission.[34][49][53] At these wavelengths the radio waves spread out in all directions and cannot be focused on a distant receiver.[33][34][49][52][60] Long range wireless power transmission was only achieved in the 1960s with the development of microwave technology.[53] Tesla's world power transmission scheme remains today what it was in Tesla's time: a bold, fascinating dream.[46][52]
High-frequency electrical safety[edit]
The 'skin effect'[edit]
The dangers of contact with high-frequency electric current are sometimes perceived as being less than at lower frequencies, because the subject usually does not feel pain or a 'shock'. This is often erroneously attributed to skin effect, a phenomenon that tends to inhibit alternating current from flowing inside conducting media. It was thought that in the body, Tesla currents travelled close to the skin surface, making them safer than lower-frequency electric currents.
Although skin effect limits Tesla currents to the outer fraction of an inch in metal conductors, the 'skin depth' of human flesh at typical Tesla coil frequencies is still of the order of 60 inches (150 cm) or more.[61][62][63][64][65] This means high-frequency currents will still preferentially flow through deeper, better conducting, portions of an experimenter's body such as the circulatory and nervous systems. The reason for the lack of pain is that a human being's nervous system does not sense the flow of potentially dangerous electric currents above 15–20 kHz; essentially, for nerves to be activated, a significant number of ions must cross their membranes 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, anecdotal evidence among Tesla coil experimenters indicates 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, solid state or vacuum tube Tesla coils operating at relatively low frequencies (tens to hundreds of kHz). It is possible to generate very high frequency currents (tens to hundreds of MHz) that do have a smaller penetration depth in flesh. These are often used for medical and therapeutic purposes such as electrocauterization and diathermy. The designs of early diathermy machines were based on Tesla coils or Oudin coils.
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 sudden pulse of current can cause involuntary spasms of major muscle groups electric shock and may induce life-threatening ventricular fibrillation and even cardiac arrest. Even lower power vacuum tube or solid state Tesla coils can deliver RF currents 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 metallic mail suit to prevent dangerous currents from entering their bodies.
The most serious dangers associated with Tesla coil operation are associated with the primary circuit. It 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 forms a circuit that may conduct lethal, low-frequency current from the primary into the person.
Further, great care must be taken when working on the primary section of a coil even when it has been disconnected from its power source for some time. The tank capacitors can remain charged for days with enough energy to deliver a fatal shock. Proper designs always include 'bleeder resistors' to bleed off stored charge from the capacitors. In addition, a safety shorting operation is performed on each capacitor before any internal work is performed.[66]
Related patents[edit]
- Tesla's patents
- See also: List of Tesla patents
- "Electrical Transformer Or Induction Device". U.S. Patent No. 433,702, August 5, 1890[67]
- "Means for Generating Electric Currents", U.S. Patent No. 514,168, February 6, 1894
- "Electrical Transformer", Patent No. 593,138, November 2, 1897
- "Method Of Utilizing Radiant Energy", Patent No. 685,958 November 5, 1901
- "Method of Signaling", U.S. Patent No. 723,188, March 17, 1903
- "System of Signaling", U.S. Patent No. 725,605, April 14, 1903
- "Apparatus for Transmitting Electrical Energy", January 18, 1902, U.S. Patent 1,119,732, December 1, 1914 (available at U.S. Patent 1,119,732
- Others' patents
- J. S. Stone, U.S. Patent 714,832, "Apparatus for amplifying electromagnetic signal-waves". (Filed January 23, 1901; Issued December 2, 1902)
- A. Nickle, U.S. Patent 2,125,804, "Antenna". (Filed May 25, 1934; Issued August 2, 1938)
- William W. Brown, U.S. Patent 2,059,186, "Antenna structure". (Filed May 25, 1934; Issued October 27, 1936).
- Robert B. Dome, U.S. Patent 2,101,674, "Antenna". (Filed May 25, 1934; Issued December 7, 1937)
- Armstrong, E. H., U.S. Patent 1,113,149, "Wireless receiving system". 1914.
- Armstrong, E. H., U.S. Patent 1,342,885, "Method of receiving high frequency oscillation". 1922.
- Armstrong, E. H., U.S. Patent 1,424,065, "Signalling system". 1922.
- Gerhard Freiherr Du Prel, U.S. Patent 1,675,882, "High frequency circuit". (Filed August 11, 1925; Issued July 3, 1928)
- Leydorf, G. F., U.S. Patent 3,278,937, "Antenna near field coupling system". 1966.
- Van Voorhies, U.S. Patent 6,218,998, "Toroidal helical antenna"
- Gene Koonce, U.S. Patent 6,933,819, "Multifrequency electro-magnetic field generator". (Filed October 29, 2004; Issued August 23, 2005)[68]
See also[edit]
- Bifilar coil
- Henry Leroy Transtrom, an inventor and showman who worked with high voltage electricity.
- List of Tesla patents
- Wireless energy transfer
- ^ a b c Uth, Robert (December 12, 2000). "Tesla coil". Tesla: Master of Lightning. PBS.org. Retrieved 2008-05-20.
- ^ Dommermuth-Costa, Carol (1994). Nikola Tesla: A Spark of Genius. Twenty-First Century Books. p. 75. ISBN 0-8225-4920-4.
- ^ "Tesla coil". Museum of Electricity and Magnetism, Center for Learning. National High Magnetic Field Laboratory website, Florida State Univ. 2011. Retrieved September 12, 2013.
- ^ "Instruction and Application Manual" (PDF). Model 10-206 Tesla Coil. Science First, Serrata, Pty. educational equipment website. 2006. p. 2. Retrieved September 12, 2013.
- ^ a b c d e f g Cheney, Margaret (2011). Tesla: Man Out of Time. Simon and Schuster. p. 87. ISBN 1-4516-7486-4.
- ^ Constable, George; Bob Somerville (2003). A Century of Innovation: Twenty Engineering Achievements that Transformed Our Lives. Joseph Henry Press. p. 70. ISBN 0-309-08908-5.
- ^ Smith, Craig B. (2008). Lightning: Fire from the Sky. Dockside Consultants Inc. ISBN 0-615-24869-1.
- ^ a b c Plesch, P. H. (2005). High Vacuum Techniques for Chemical Syntheses and Measurements. Cambridge University Press. p. 21. ISBN 0-521-67547-2.
- ^ a b Tilbury, Mitch (2007). The Ultimate Tesla Coil Design and Construction Guide. New York: McGraw-Hill Professional. p. 1. ISBN 0-07-149737-4.
- ^ a b Ramsey, Rolla (1937). Experimental Radio (4th ed.). New York: Ramsey Publishing. p. 175.
- ^ Mazzotto, Domenico (1906). Wireless telegraphy and telephony. Whittaker and Co. p. 146.
- ^ Sarkar, T. K.; Mailloux, Robert; Oliner, Arthur A. et al. (2006). History of Wireless. John Wiley & Sons. pp. 286, 84. ISBN 0-471-78301-3.
- ^ a b "Unfortunately, the common misunderstanding by most people today is that the Tesla coil is merely a device that produces a spectacular exhibit of sparks which tittilates audiences. Nevertheless, its circuitry is fundamental to all radio transmission" Belohlavek, Peter; Wagner, John W (2008). Innovation: The Lessons of Nikola Tesla. Blue Eagle Group. p. 110. ISBN 9876510096.
- ^ Naidu, M. S.; Kamaraju, V. (2013). High Voltage Engineering. Tata McGraw-Hill Education. p. 167. ISBN 1259062899.
- ^ Corum, J. F.; Corum, K. L. (2001). "RF coils, helical resonators and voltage magnification by coherent spatial modes". 5th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service, 2001. TELSIKS 2001 (IEEE) 1: 10.
- ^ Nicholson, Paul. "TSSP: Secondary Basics - Tesla Secondary Simulation Project" (PDF).
- ^ This is an early electronics magazine.
- ^ (Norrie, pg. 34–35)
- ^ N. Tesla, US patent No. 1, 119, 732. "I employ a terminal of relatively small capacity, which I charge to as high a pressure as practicable." (emphasis added) Tesla's lightning rod, U.S. Patent 1,266,175, goes more into this subject. The reader is also referred to the U.S. Patent 645,576, U.S. Patent 649,621, U.S. Patent 787,412, and U.S. Patent 1,119,732.
- ^ Patent 1119732, lines 53 to 69; In order to develop the greatest energy in the circuit without flashover to the coil, Tesla elevated the conductor with a large radius of curvature or was composed of separate elements which in conglomeration had a large radius.
- ^ In Selected Patent Wrappers from the National Archives, by John Ratzlaff (1981; ISBN 0-9603536-2-3), a variety of terminals was described by Tesla. Besides the torus-shaped terminal, he applied for hemispherical and oblate terminals. A total of five different terminals were applied for, but four were rejected.
- ^ US Patent No. 649621, Nikola Tesla, Apparatus for transmission of electrical energy, filed February 19, 1900, granted May 15, 1900
- ^ de Queiroz, Antonio Carlos M. "Generalized Multiple LC Resonance Networks". International Symposium on Circuits and Systems (IEEE) 3: 519–522.
- ^ de Queiroz, Antonio Carlos M. "Designing a Tesla Magnifier". Retrieved April 12, 2015.
- ^ This is equivalent to hundreds of thousands of horsepower
- ^ Gottlieb, Irving (1998). Practical Transformer Handbook. Newnes. p. 551. ISBN 0080514561.
- ^ "Corona Discharge Electrographic Imaging Technology" Kirlianlab.com.
- ^ Interview with ArcAttack on Odd Instruments
- ^ Duckon 2007-Steve Ward's Singing Tesla Coil video
- ^ Tesla Music Band
- ^ The Electrum Project, Lightning On Demand, Brisbane CA
- ^ http://www.guinnessworldrecords.com/records-5000/most-powerful-conical-coil-/
- ^ a b c Curty, Jari-Pascal; Declercq, Michel; Dehollain, Catherine; Joehl, Norbert (2006). Design and Optimization of Passive UHF RFID Systems. Springer. p. 4. ISBN 0387447105.
- ^ a b c d e f Shinohara, Naoki (2014). Wireless Power Transfer via Radiowaves. John Wiley & Sons. p. 11. ISBN 1118862961.
- ^ a b c d e f g h Lee, C.K.; Zhong, W.X.; Hui, S.Y.R. (September 5, 2012). Recent Progress in Mid-Range Wireless Power Transfer (PDF). The 4th Annual IEEE Energy Conversion Congress and Exposition (ECCE 2012). Raleigh, North Carolina: Inst. of Electrical and Electronic Engineers. pp. 3819–3821. Retrieved November 4, 2014.
- ^ a b Tesla, Nikola (May 20, 1891) Experiments with Alternate Currents of Very High Frequency and Their Application to Methods of Artificial Illumination, lecture before the American Inst. of Electrical Engineers, Columbia College, New York. Reprinted as a book of the same name by. Wildside Press. 2006. ISBN 0809501627.
- ^ a b c Wheeler, L. P. (August 1943). "Tesla's contribution to high frequency". Electrical Engineering (IEEE) 62 (8): 355–357. doi:10.1109/EE.1943.6435874. ISSN 0095-9197.
- ^ Tesla was notoriously secretive about the distance he could transmit power. One of his few disclosures of details was in the caption of fig. 7 of his noted magazine article: The Problem of Increasing Human Energy, Century magazine, June 1900. The caption reads: "EXPERIMENT TO ILLUSTRATE AN INDUCTIVE EFFECT OF AN ELECTRICAL OSCILLATOR OF GREAT POWER - The photograph shows three ordinary incandescent lamps lighted to full candle-power by currents induced in a local loop consisting of a single wire forming a square of fifty feet each side, which includes the lamps, and which is at a distance of one hundred feet from the primary circuit energized by the oscillator. The loop likewise includes an electrical condenser, and is exactly attuned to the vibrations of the oscillator, which is worked at less than five percent of its total capacity."
- ^ Leyh, G. E.; Kennan, M. D. (September 28, 2008). Efficient wireless transmission of power using resonators with coupled electric fields (PDF). NAPS 2008 40th North American Power Symposium, Calgary, September 28–30, 2008. Inst. of Electrical and Electronic Engineers. pp. 1–4. doi:10.1109/NAPS.2008.5307364. ISBN 978-1-4244-4283-6. Retrieved November 20, 2014.
- ^ Sazonov, Edward; Neuman, Michael R (2014). Wearable Sensors: Fundamentals, Implementation and Applications. Elsevier. pp. 253–255. ISBN 0124186661.
- ^ Agbinya, Johnson I. (February 2013). "Investigation of near field inductive communication system models, channels, and experiments" (PDF). Progress In Electromagnetics Research B (EMW Publishing) 49: 130. Retrieved January 2, 2015.
- ^ Bolic, Miodrag; Simplot-Ryl, David; Stojmenovic, Ivan (2010). RFID Systems: Research Trends and Challenges. John Wiley & Sons. p. 29. ISBN 0470975660.
- ^ Tesla, Nikola (June 1900). "The Problem of Increasing Human Energy". Century Magazine (New York: The Century Co.). Retrieved November 20, 2014.
- ^ a b US Patent No. 645576, Nikola Tesla, System of transmission of electrical energy, filed September 2, 1897; granted March 20, 1900
- ^ Tesla, Nikola (March 5, 1904). "The Transmission of Electric Energy Without Wires". Electrical World and Engineer (McGraw Publishing Co.) 43: 23760–23761. Retrieved November 19, 2014., reprinted in Scientific American Supplement, Munn and Co., Vol. 57, No. 1483, June 4, 1904, p. 23760-23761
- ^ a b c d Broad, William J. (May 4, 2009). "A Battle to Preserve a Visionary's Bold Failure". New York Times (New York: The New York Times Co.). pp. D1. Retrieved November 19, 2014.
- ^ Carlson 2013 Tesla: Inventor of the Electrical Age, p. 209-210
- ^ Carlson 2013 Tesla: Inventor of the Electrical Age, Ch. 14 & 15, p. 302-367
- ^ a b c d e f g h i Coe, Lewis (2006). Wireless Radio: A History. McFarland. p. 112. ISBN 0786426624.
- ^ Hawkins, Lawrence A. (February 1903). "Nikola Tesla: His Work and Unfulfilled Promises". The Electrical Age 30 (2): 107–108. Retrieved November 4, 2014.
- ^ a b Carlson, W. Bernard (2013). Tesla: Inventor of the Electrical Age. Princeton University Press. pp. 294, 301. ISBN 1400846552.
- ^ a b c d Tomar, Anuradha; Gupta, Sunil (July 2012). "Wireless power Transmission: Applications and Components". International Journal of Engineering Research & Technology 1 (5). ISSN 2278-0181. Retrieved November 9, 2014.
- ^ a b c Brown, William C. (1984). "The history of power transmission by radio waves". MTT-Trans. on Microwave Theory and Technique (Inst. of Electrical and Electronic Engineers) 32 (9): 1230–1234. Retrieved November 20, 2014.
- ^ a b Dunning, Brian (January 15, 2013). "Did Tesla plan to transmit power world-wide through the sky?". The Cult of Nikola Tesla. Skeptoid.com. Retrieved November 4, 2014.
- ^ "Life and Legacy: Colorado Springs". Tesla: Master of Lightning - companion site for 2000 PBS television documentary. PBS.org, US Public Broadcasting Service website. 2000. Retrieved November 19, 2014.
- ^ a b Dunning, Brian (January 15, 2013). "Did Tesla cause a field of light bulbs 26 miles away to illuminate wirelessly?". The Cult of Nikola Tesla. Skeptoid.com. Retrieved November 4, 2014.
- ^ Tesla, Nikola (1977). Marinčić, Aleksandar, ed. Colorado Springs Notes, 1899-1900. Beograd, Yugoslavia: The Nikola Tesla Museum.
- ^ O'Neill, John J. (1944). Prodigal Genius: The life of Nikola Tesla. Ives Washburn, Inc. p. 193.
- ^ Wearing, Judy (2009). Edison's Concrete Piano: Flying Tanks, Six-Nippled Sheep, Walk-On-Water Shoes, and 12 Other Flops From Great Inventors. ECW Press. p. 98. ISBN 1554905516.
- ^ a b "Dennis Papadopoulos interview". Tesla: Master of Lightning - companion site for 2000 PBS television documentary. PBS.org, US Public Broadcasting Service website. 2000. Retrieved November 19, 2014.
- ^ General Tesla coil construction plans
- ^ Skin Effect/Material Constants
- ^ Re: skin depth in round conductors Re: 8 kHz Tesla Coil
- ^ Re: Mini Tesla. Dangerous Stunts
- ^ An independent analysis for a small coil yields 2.5 inches in normal saline, which is just as serious a health hazard as 60 inches for practical purposes.[citation needed]
- ^ Tesla Coils Safety Information". pupman.com.
- ^ History of Wireless By Tapan K. Sarkar, et al. ISBN 0-471-78301-3
- ^ A Multifrequency electro-magnetic field generator that is capable of generating electro-magnetic radial fields, horizontal fields and spiral flux fields that are projected at a distance from the device and collected at the far end of the device by an antenna.
Further reading[edit]
- Operation and other information
- Armagnat, H., & Kenyon, O. A. (1908). The theory, design and construction of induction coils. New York: McGraw.
- Haller, G. F., & Cunningham, E. T. (1910). The Tesla high frequency coil, its construction and uses. New York: D. Van Nostrand Co.
- Iannini, R. E. (2003). Electronic gadgets for the evil genius: 21 build-it-yourself projects. TAB electronics. New York: McGraw-Hill. Pages 137 – 202.
- Corum, Kenneth L. and James F. "Tesla Coils and the Failure of Lumped-Element Circuit Theory"
- Nicholson, Paul, "Tesla Secondary Simulation Project" (Current state of the art in rigorously describing Tesla coil secondary behavior through theoretical analysis, simulation and testing of results in practice)
- Bill Beaty "Nikola Tesla Coil Information".
- Vujovic, Ljubo, "Tesla Coil". Tesla Memorial Society of New York.
- Hickman, Bert, "Tesla Coil Information Center"
- Cooper, John. F., "Magnifying Transmitter early-type circuit diagram; Later-type circuit diagram". Tesla-Coil.com
- Electrical World
- "The Development of High Frequency Currents for Practical Application"., The Electrical World, Vol 32, No. 8.
- "Boundless Space: A Bus Bar". The Electrical World, Vol 32, No. 19.
- Other publications
- A. L. Cullen, J. Dobson, "The Corona Breakdown of Aerials in Air at Low Pressures". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 271, No. 1347 (February 12, 1963), pp. 551–564
- Bieniosek, F. M., "Triple Resonance Pulse Transformer Circuit". Review of Scientific Instruments, 61 (6).
- Corum, J. F., and K. L. Corum, "RF Coils, Helical Resonators and Voltage Magnification by Coherent Spatial Modes". IEEE, 2001.
- de Queiroz, Antonio Carlos M., "Synthesis of Multiple Resonance Networks". Universidade Federal do Rio de Janeiro, Brazil. EE/COPE.
- Haller, George Francis, and Elmer Tiling Cunningham, "The Tesla high frequency coil, its construction and uses". New York, D. Van Nostrand company, 1910.
- Hartley, R. V. L., "Oscillations with Non-linear Reactances". Bell Systems Technical Journal, Alcatel-Lucent, 1936 (3), 424-440.
- Norrie, H. S., "Induction Coils: How to make, use, and repair them". Norman H. Schneider, 1907, New York. 4th edition.
- Reed, J. L., "Greater voltage gain for Tesla transformer accelerators", Review of Scientific Instruments, 59, p. 2300, (1988).
Reed, J. L., "Tesla transformer damping", Review of Scientific Instruments, 83, 076101-1 (2012).
- Reed, J. L., "Conduction-coupled Tesla transformer," Review of Scientific Instruments, 86,035113 (2015)
- Curtis, Thomas Stanley, High Frequency Apparatus: Its Construction and Practical Application. Everyday Mechanics Co., 1916.
- numerous academic IEEE publications [1]
External links[edit]
|Wikimedia Commons has media related to Tesla coils.
- Tesla coil at DMOZ


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text:
October 26, 2006 4:00 AM PDT
On Web standards, Libertarian candidates win
- Related Stories
Google unveils election mashupOctober 22, 2006
Lieberman defeat a win for 'Netroots' politics?August 9, 2006
Political bloggers may get federal protectionMarch 9, 2006
The coming crackdown on bloggingMarch 3, 2005
Is the PC a political machine?October 5, 2004
Bloggers drive hoax probe into Bush memosSeptember 10, 2004
Hail to the 'coder in chief'July 22, 2004
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Perspective: Don't get mad, get evenNovember 11, 2002
(continued from previous page)
"The notion of being able to reach the full range of people that make up voters is good enough reason to be using valid markup (language)," said Daly from the W3C. "The most transparent and self-serving of reasons is the most important reason in a campaign: You want people to know about you and you want to encourage them to vote for you, so there's no reason to put impediments based on markup."
Out of roughly 535 members of Congress, News.com found that only four incumbent House members and no senators running for re-election passed the test. The four incumbents with passing grades: Reps. John Lewis of Georgia and Dutch Ruppersberger of Maryland, both Democrats, and Dave Reichert of Washington state and Mike Sodrel of Indiana, both Republicans.
House staffers were "really all about being W3C compliant for any official site," said Jim Metzler of Reach Out Communications in Timonium, Md., who developed Ruppersberger's campaign Web site. "Occasionally things get out of sync and we have to go in and make a couple of changes to make sure it's back in compliance."
The Web design field is replete with cautionary tales about how sites that don't follow industry guidelines risk crashing browsers or vanishing from search engines. A simple example would be the <title> HTML tag, which search engines scan when trying to decide how to rank a Web site. A typo could quietly remove the offending Web site from search engines' indexes.
"In this day and age, the Internet is the main source of information for everything, especially in a political campaign," said Josh Feinauer, the campaign Webmaster for LaVar Christensen, a Republican seeking a House seat in Utah. "You've got to make sure everything works, that it has all of those standards."
Open-source activist, political candidate
To be sure, even strict compliance with HTML and XML standards hardly guarantees an attractive Web site, as Parker4Congress.com and RogerIPrice.com demonstrate. By way of analogy, someone who can speak grammatically correct English may have a limited vocabulary, and a photographer who can operate the dials of a camera flawlessly may have no sense of beauty or perspective.
Josh Hansen, a House candidate with the Independent American Party of Nevada, is considered--at least by his father--to be a "Web standards compliance freak." The IAP of Nevada is an offshoot of the Constitution Party and stresses downsizing the federal government and stopping illegal immigration.
Hansen says that his inspiration for adherence to Web standards came from Zeldman.com and Jeffrey Zeldman's book "Designing With Web Standards." Also, as a Linux and Apple Computer Macintosh user, he wasn't using Internet Explorer and knew firsthand that not all Web browsers render a page identically.
It's not "that people are making a conscious decision not to follow Web standards," Hansen said. "It's that most people don't understand Web standards. I think a lot of Web development tools have turned a lot of people who are document writers into what they think are Web guys because they can take a word document and turn it into an HTML document and throw it up online."
But it was the Libertarian candidates who seemed to be the most tech-savvy. The party's vice presidential nominee in 1996, Jo Jorgensen, was head of a small software company, and its 2004 presidential nominee was an assembly language programmer. Its platform talks about Internet freedoms and "eliminating all restrictions" on the "private development, sale, and use of encryption technology."
Mike Sylvia, a FedEx employee, is campaigning as a Libertarian for a House seat in New York. He says he runs Debian Linux on his home computer and uses Mozilla Composer to build his pages. "I'm a member of the Ithaca Free Software Association," Sylvia said. "They're independent spirits."
The list of board members for the national Libertarian Party is no less geekish: a software engineer; a database consultant; an author of a book on Linux system administration; the CEO of a Web application company; and the creator of PocketMoney personal finance software for Palm handhelds.
"Can you find another political party with a tech-savvy board like this?" said Cory, the Libertarians' national chairman. "I can tell you it's not going to happen."
Page 1 | 2
See more CNET content tagged:
candidate, industry standard, geek, survey, Republican
7 commentsJoin the conversation! Add your comment
- Maybe I'm having trouble counting, but...
- Looking at the list of websites, it seems that Republicans and Libertarians each have seven valid sites... how is it that Republicans come in "a close second"?
- Like Reply Link Flag
- the point?
- I think i missed it.... Here's 10 minutes of my life I'll never get back.
- Like Reply Link Flag
- Incumbents vs Challengers
- It seems the big difference is incumbents vs challengers, which makes sense since challengers need to promote themselves a bit more.
On the whole, I agree with the other poster. This was an utter waste of time.
Adhering perfectly to 'web standards' just isnt that important. For starters, neither FF or IE are even fully compliant themselves! Its a nice thing to discuss at the campus coffee shop so that other college comp sci students will think you're a hardcore h4xxor. But as long as the major browsers can all access your site, thats all that matters. The REAL web standard is that your site displays correctly in IE and FF.
- Like Reply Link Flag
- Yes and no ...
- It's true there are no house members elected as Libertarians, but Congressman Ron Paul (R-Texas) is a former Presidential candidate for the Libertarian Party, and without doubt a genuine libertarian, regardless of his current party label.
- Like Reply Link Flag
- L vs l
- Ron Paul is certainly a small l-libertarian. But he's certainly not in office as a large-L libertarian, which is what our article said.
BTW check out his opponent's web site. They're calling Paul a libertarian -- using it against him in radio/TV ads. It might even work. Seems to be a tight race.
- Like Reply Link Flag
- Who graded these sites?
- The first site on the list isn't standards compliant. It might validate, but it's built in tables. There is criteria extending far beyond W3C validation for a standards-based site.
- Like Reply Link Flag


text:
The Aging and Memory in the African American Community Conference, scheduled for June 2nd, 2012, is the signature educational event organized by the PreSERVE Coalition designed to initiate healthy change for individuals and community.
The PreSERVE Coalition is a group of individuals from healthcare, service organizations and the community, collaborating on initiatives that support the health and well being of older adult African Americans in the Portland, Oregon metropolitan area. They focus particularly on brain health and the many aspects of preserving memory.
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The keynote speaker is; Monica Willis Parker, MD, Assistant Professor, Department of Medicine, Division of Geriatric Medicine and Gerontology at Emory University and Principal Investigator for the Registry for Remembrance.
Dr. Parker will present on the association between memory and healthful behaviors, including the role played by chronic conditions such as diabetes, hypertension and depression. She will also share how she and her team engaged community members in health-promoting activities and increased awareness of the importance of minority involvement in research.
There will be a Special lunchtime presentation by Renee Mitchell.
A natural storyteller, Renee is an exceptional public speaker who uses humor, original poetry and her professionally trained theatrical experience to empower, motivate and delightfully entertain all types of audiences.
Student volunteers from the Humboldt and Harriett Tubman schools will hold sessions throughout the day to interview and record oral histories of elders. Each participant will have a fifteen minute interview/recording session and leave with a recording of their story.
Attendants may choose from one of the following morning workshops:
- Beating the Blues: Mental Wellness in the African-American Community. Danette C. Haynes, LCSW, Clinical Director of the OHSU Avel Gordly Center for Healing, will provide information about the signs of anxiety, depression and Posttraumatic Stress Disorder, coping strategies and skills for mental well-being and culturally-sensitive resources available to the African-American community
- Yoga and Tai Chi. Yoga and Tai Chi offer a number of benefits including a gentle form of exercise that does not stress joints and muscles, stress reduction, improved strength, balance and stability. Join Allyson Spencer as she presents the basics of these ancient disciplines and walks attendees through simple exercises that can be done at home.
- Improving the Health of the African American Community: A closer look at the connection between diabetes and brain health. Dr. Jeannine Skinner, geriatric neuropsychology fellow in the Department of Psychiatry and Behavioral Sciences at the University of Washington School of Medicine, will discuss current research on the role of insulin in memory loss disorders, and her current research examining how physical activity affects memory and other thinking abilities in African Americans at risk for diabetes.
- Early Warning Signs of Alzheimer's and Early Warning Signs of Caregiver Stress. This workshop will be co-presented by Pamela Mottola, Client Services Manager, Alzheimer's Association, and Celesta Paul, family caregiver.
- Greens, Beans and Dark Things: Eating for Pleasure and Health on a Budget. By Joyce McGee, nutrition educator and caterer with Pans, Pots & Skillets.American community
Afternoon workshops (choose one):
- Beating the Blues: Mental Wellness in the African-American Community (repeat)
- Improving the Health of the African American Community (repeat)
- Early Warning Signs of Alzheimer's and Early Warning Signs of Caregiver Stress (repeat)
- Don't Just Talk About it, Be About It! Attendees will be invited to brainstorm ideas on how to take the message of a healthy lifestyle and healthy brain out into their communities.
Click the link below for an article with more information about the prevalence of Alzheimer's among African Americans.
African Americans and Hispanics are More Likely to Develop Alzheimer's
For more information and a detailed itinerary for the Aging and Memory in the African American Community Conference, please visit this ling to the PreSERVE Coalition's website: http://www.preservecoalition.org/
The 2012 conference is made possible thanks to these generous sponsors: Layton Aging & Alzheimer's Disease Center, OHSU Multnomah County Aging & Disability Services, Providence ElderPlace, AARP Oregon, Volunteers of America, Oregon, Black United Fund, Alzheimer's Association Oregon Chapter, The Links, Inc.,
Portland Chapter
Donations can be made to the Layton Aging & Alzheimer's Disease Center through this link: https://www.ohsu.edu/foundation/giving/default.cfm?fcode=AGINGALZ&src=WEBENDEAR


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12 Designer Gowns That You Need To See!
Anjolique BridalA mermaid silhouette will show off your curves and make you feel like a star.
Kisui BerlinA simple white gown and French lace is classic and sophisticated.
Somsi CoutureRomantic ruffles and floor length veils are a must for any fairytale wedding.
Lillen CollectionThis Vneck fit-and-flare will highlight your curves and will look spectacular with the right earrings.
Jasmine CollectionAiry handkerchief tiers and illusion necklines are so on trend!
DemetriosConvertible dresses that allow you to seamlessly change from ceremony to reception are all the rage.
Justin AlexanderWe love sweet and sexy off-the-shoulder styles.
Angelina Couture BridalGathered skirts and fitted bodices will define your shape and make you look like a princess.
Tony Ward BridalWe can't get enough hand pleating and fluttery lace sleeves!
Sweetheart GownsBeaded skirts can sometimes be overpowering, but we love this dainty design.
Olga KvitkoGowns by Olga are ultra feminine and flirty. A coral sash is a lovely touch!
Carrafina CoutureLace tiers are in and don't you dare think about walking down that isle without a beaded sash.
Multiple wedding dress and accessories designers and special occasion labels display their latest collections at Couture Show so that we're the first to see! Be sure to check these guys out when shopping for THE dress.
> See our favorite headpieces and veils at Couture
> See our favorite jewelry from bridal fashion week!


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Eddie Howe celebrated a year in charge of Burnley with the superb victory at (then) third placed Middlesbrough, inflicting only their second home league defeat of the season, writes Chris Ellison.
The dominant performance however was equally as pleasing as the three points as Burnley totally dominated, especially in the at times embarrassingly one sided first half.This latest victory on the road was, amazingly, Howe's 12th away win out of the 25 away league games he has been in charge of since his appointment on 16th January 2011. Crude I know, but if you allow me to add his 2010/11 fixtures to those so far in 2011/12, Howe has been in charge of 47 league games (1 more than a full season) and 25 away games (2 more than a full season). It really is a great time to follow the Clarets away from home!
I have been fortunate enough to be a regular attendee at away games since the early 90s and I'm sure many seasoned Burnley fans will agree with me – Burnley just don't win that many away games per 'season'. You have to go back to the 2001/02 season when Burnley threatened to take the Championship by storm by winning ten away games, only to eventually miss out on a play-off place, to see a number of victories that comes close to Howe's performance. Burnley won less still in the 1993/94, 1999/2000 and 2008/09 promotion seasons, such is our usual dominance at 'Fortress Turf'.
So what is Howe's secret? Well first, I have included a crude statistic and he has had two more away games than a regular season, but it's still impressive. My personal opinion is that we are set up in such a way that makes us a better away team; I think we struggle at times to impose ourselves on games at Turf Moor. We have a forward line which has the classic ability to hit teams on the break and when we put the opposition under pressure and really go full throttle, like the first half at Middlesbrough, we look an absolute force.
We have a state where almost all of our forward players are comfortable switching from left to right to playing down the middle and it means we are so flexible and at times difficult to second guess.
Now for some highlights out of the 12 away victories:
- 2010/11 Portsmouth – This was Howe's second away game and his first away victory. Burnley took the game to Portsmouth from the off, one and two touch passing in neat triangles, switching the play and getting the ball wide at every opportunity. The winning goal was an absolute peach, some would say a collector's item too, as a Dean Marney overhead kick flew in to the net in front of the travelling fans
- 2010/11 PNE – We all remember this one surely as Burnley got back to winning ways at Deepdale. Thousands of Burnley fans were packed in to the Bill Shankly Kop as a flowing move was started and finished by the energetic Jack Cork, running about 40 yards from his initial pass to head home the winner…the Burnley end in the last ten minutes or so was bouncing, back to the great King Arthur Sunday afternoon days!
- 2010/11 Derby – We had lost our previous three away games with poor performances, especially the 4-0 reverse at Leicester where we were torn apart, however we got back to winning ways at a relatively happy hunting ground for us. There was a buzz in the Burnley end as Chris McCann was a surprise inclusion on the team sheet following months out with injury and McCann added the icing on a very sweet tasting cake as he scored a superb fourth goal as Burnley ran out 4-2 victors
- 2011/12 Millwall – In blistering heat Burnley produced a superb second half defensive display to record our first clean sheet in 24 games. Burnley scored towards the end of the first half via our thoroughly effective corner routine and the whole team, not least Lee Grant and the defence, handled everything that Millwall threw at them in the second half as the fans came away celebrating and feeling like we had finally turned a corner defensively
- 2011/12 Hull – In a crazy final 13 minutes Burnley dragged themselves from the prospect of being in the relegation places at the final whistle to obtaining a confidence boosting win that has kick started our 2011/12 season. I wasn't actually at this game but listened to it on Radio Lancashire and it sounded like Burnley had turned in an absolutely turgid display heading in to the final 13 minutes of the game 2-0 down. We all know the rest, it's the stuff of dreams, as David Edgar popped up with two goals in three minutes to give the Clarets what looked like being an unlikely point…only for Jay Rodriguez to get an early shot away from the edge of the area deep in to injury time to send my living room into raptures!
- 2011/12 West Ham – Howe called this his best result as Burnley manager, some may call it a smash and grab, but it was a thoroughly solid performance. We didn't have many opportunities and they missed a couple of glaring chances but when you come from a goal down at the Boleyn Ground against a very good West Ham side you take it. Both Burnley goals were superb too, great crosses and bullet headers
- 2011/12 Middlesbrough – For me this was Burnley's performance of the season so far, if not the best performance under Howe. Cliché warning but we really did take the game by the scruff of the neck from kick off, put Middlesbrough on the back foot, dictated the tempo and had innumerate chances. We took the lead through our routine corner and doubled our advantage via a Kieran Trippier thunderbolt. We then showed a different side to our play in the second half as we were far less gung-ho, defended stoutly and protected the lead. The atmosphere and smiles on the faces of the Burnley fans said it all.
Like I said at the start of this piece, it really is a superb time to be following the Clarets away from home as we are turning in some fantastic displays of football at times. All that remains is for this away form to continue, we can cope with a few defeats along the way but it would be great to kick on at Turf Moor, make it a fortress again and really take this division by storm!
Up the Clarets!


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Research firm IDC is out today with new data on the state of the tablet and 2-in-1 market in the first quarter of 2014. As you might expect after Apple's most recent earnings report, Q1 unit shipments of iPad were down by 3 million from 19.5 million to 16.4 million between 2013 and 2014. For its part, Apple attributes its Q1 2013 iPad sales as inflated due to demand for iPad mini in Q4 2012 being fulfilled in the following quarter when supply was less constrained.
That may be, but the iPad also saw a drop in tablet market share between the first quarter of 2013 and the first quarter of 2014. According to IDC's data, Apple dropped from 40.2% market share in Q1 2013 to 32.5% market share in Q1 2014 while Samsung saw unit shipments increase as well as marketshare. Despite Samsung's gains, though, Apple still dominates the tablet market more than any other one company leading Samsung by 10 percentage points in market share.
"The rise of large-screen phones and consumers who are holding on to their existing tablets for ever longer periods of time were both contributing factors to a weaker-than-anticipated quarter for tablets and 2-in-1s," said Tom Mainelli, IDC Program Vice President, Devices and Displays. "In addition, commercial growth has not been robust enough to offset the slowing of consumer shipments."
While Apple is indeed leading in market share with nearly a third of tablets (and 2-1 devices being included) sold being an iPad, the data does trend toward growth slowing down and not picking up as 2013 saw fewer tablets sold than 2012 per Gartner and this year already continuing that direction. However, increased unit shipments from Samsung, Lenovo, and others do show a slight increase in tablets sold in the first quarter of each year.
Leave a Reply
7 Responses to "Apple's iPad maintains a narrowing lead, still almost a third of all tablets sold"
I think we could say that mobile phones are splitting in two groups:
-phones (primary function – talking)
-personal (ultra-portable) multimedia devices – large screen "phones"
In short those multimedia "phones" are great because they're small enough not to represent a burden when carrying in a bag, jacket pocket and so on, jet they offer full web "in-touch"!! (future might bring glasses with a retina projector and a connected device in a pocket)
Old small tablets are becoming a niche; I would not look at them twice anymore (not that portable since cumbersome and not productive).
Tablets need to evolve into bigger and more powerful devices; 13″ till 16″. Practically a light, portable interactive screen I can take with me from the living room to my home office or even bedroom,… Maybe I'll take it to work, or a work trip.
I hope Apple will bring out the iPad-Pro 13″, otherwise I'll order the big Samsung tablet.


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Find hotels in Abstatt using the list and search tools below. Search for cheap and discounted hotel and motel rates in or close to Abstatt, Germany for your corporate or personal leisure travel. Explore the most favored Abstatt hotel rooms. Review the Abstatt hotel list below to find the perfect lodging. We also have a map of the Abstatt hotels. Booking 5+ Rooms? Find Abstatt Group Hotel DealsThe Abstatt center point is approximately 19 miles from Gottlieb-Daimler Stadion and 20 miles from Central Railway Station.
Abstatt Hotels/Accommodations
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Visit mda.org/muscle to learn more about the 2013 MDA telethon.
About MDA
The Muscular Dystrophy Association is the world's leading nonprofit health agency dedicated to finding treatments and cures for muscular dystrophy, amyotrophic lateral sclerosis (ALS) and other neuromuscular diseases. It does so by funding worldwide research; by providing comprehensive health care services and support to MDA families nationwide; and by rallying communities to fight back through advocacy, fundraising and local engagement. Visit mda.org and follow us at facebook.com/MDAnational and @MDAnews.
Read the full story at http://www.prweb.com/releases/2013/9/prweb11081581.htm.
|Source: PRWeb
Copyright©2012 Vocus, Inc.
All rights reserved


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You can now invite anyone to meet at your favorite Starbucks.
Limited-time feature
27 year old man | Baltimore, MD, USA | Seeking men 21-32 within 40 miles
Finding my way in life, and looking for someone to join me on this crazy trip :-)
Hey, my name is Anton. I just graduated from medical school in Europe and am back in the USA after almost 7 years. I am a pretty even-keeled and optimistic person, and am looking for someone similar. I open up somewhat slowly, but once I have accepted someone into my heart, I will do everything for them. Being open to my family and friends about who I am is probably one of the most important things for me, and I want to be with someone who is comfortable in their own skin. I am driven to achieve my goals and finding someone who is passionate and excited about what they do in life is something that is important to me. Sarcasm is a way I find humor in things at times, that said, I am an empathetic person and kindness is a must. I am not a big fan of people who think too highly of themselves. Traveling is my passion. I have been fortunate enough to have traveled to quite a few places around the world, and am looking for someone with whom to discover new places with, whether locally or abroad. I enjoy going out and having a crazy night, but just staying in on a Friday or Saturday night is perfect as well. I love going to local shows to listen to some awesome band and enjoy a beer or two. Being an avid reader is something I take pride in, and I am most definitely looking for someone who enjoys a good book, and finding someone who enjoys the theater or other cultural events with me would be great. I like to think of myself as an open-minded and adventurous person and am hopeful to meet someone with whom I can have awesome adventures of all kinds :))
Camping , Coffee and conversation , Cooking , Dining out , Movies/Videos , Museums and art , Music and concerts , Exploring new areas , Nightclubs/Dancing , Performing arts , Political interests , Travel/Sightseeing , Video games , Volunteering , Wine tasting
Aerobics, Cycling, Dancing, Running, Swimming, Walking / Hiking
I exercise 3-4 times per week.
I like Dogs
Hopefully I will find new favorite places with someone that I meet on here :) Europe is the place where I feel the freest, Barcelona, Paris and Prague are my favorites. Istanbul is an AMAZING place. Really want to go to Thailand and India!
I am very passionate about traveling.. I love cooking and experimenting in the kitchen, TV - House of Cards, The Newsroom, Modern Family, Game of Thrones, True Blood. P90X--started it and loving it :)
Love traveling, been to many places, want to go to many more. A bit of a music nut - live music and collecting all kinds of music is a passion. Hanging out with friends and family, cooking, hiking, reading is a big thing for me. And a lot more...
Currently reading Running with Scissors by Augusten Burroughs and When Nietzsche Wept by Irvin Yalom. Plus a ton of medical books, which I seem never to make any progress with :)
Z{{Cta}} {{#if HasMoreInfo}} ?{{CtaSecondary}} {{/if}}
|What he is looking for
|6'3" (190cms)
|3'0" (91cms) to 8'11" (271cms)
|Body type:
|About average
|Slender, About average, Athletic and toned, A few extra pounds
|Black, Blue, Brown, Grey, Green, Hazel
|Auburn / Red, Black, Light brown, Dark brown, Blonde, Salt and pepper, Silver, Dark blonde, Grey, Platinum, Bald
|No Way
|No Way
|Social Drinker
|Social Drinker
|Medical / Dental / Veterinary / Fitness
|No preference
Recent med school graduate. I studied in Europe and am now back in the states studying for exams to apply to residencies.
|I'll tell you later
|No preference
|Never Married
|No preference
|Have kids:
|Wants kids:
|Definitely, Someday, Not sure
|White / Caucasian
|No preference
|I'll tell you later
|No preference
|English, Other
|No preference
|Graduate degree
|Some college, Associates degree, Bachelors degree, Graduate degree, PhD / Post Doctoral
Medical School


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Winter!: Prepare for holiday gaming!
Eve Online
I might as well have a go at this although recruitment i not my area, im more PvP management
STK-Scientific is one of the leading industrial corps in the game, some founding members still active, we make cap ships and T2 gear plus anything else that makes a buck.
Our PvP wing is very dedicated, we have good FCs that know what they doing. STK is swinging more into a megacorp style now and working up its PvP status which is very good anyways.
Basically anyone over 10m SPs is more than welcome but please be warned, we are a mature group, we work and have lives, many of us are over 30 so we swear at each other like troopers. Whislt having alot of fun laying and generally killing anything not blue we drink, many ppl you fly with may be drunk or worse, in fact we sometimes have a Friday Drunken Ops night where if you dont loose your ship you are considered not trying hard enuff and a pussy.
If ya new but generally a good easy going dude or dudette that doesnt mind colourful language and accasionally flying with the odd drunkard then send Shme a msg ingame anyways, We will prolly nickname you 'fodda' and will be throwen at the enermy for laughs. You will of course get an unlimited supply of frigates cause that never gets old.
In general we have a plan and are focused on it, centres more around PvP.
Nice seeing another Corp on here!
Where are you guys located?
Never hurts to establish a friendship in this game. We both know how far those can go!
We will be in Stain for the time being
|Post Reply
|Thread Tools


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Razer CEO Min-Liang Tan talks up new laptop
We talk with Min-Liang Tan, CEO of Razer, and self proclaimed "head gamer" about the Razer Blade laptop, and what makes Razer tick.
by Jess McDonell on
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I prefer laptops that have easy access to the fan(s) and heat sink's air intake and air exhaust. I clean out my laptop's fan and heat sink once a year to keep the laptop as cool as possible.
looks amazing..
My Razer Copperhead gaming mouse still works as great as the day I bought it. Good luck with the high price laptops!
I foresee a heating issue. There is a reason that "traditional" performance lap tops are so big. I can't image a fan that can move enough air being put into a laptop of ultrabook size.
We will see. The 3k price tag is also discouraging (AUS and USD are about equal); yes, you are paying for the LCD customizable side keys, but honestly, who the hell needs that? They need to streamline this thing for efficiency, and remove that crap.
Laptops and gaming DOT NOT MIX!.
this thing would be out of date quickly and
I should not have to say the kind of rig you could build for £2000 would eat 10 of those lappys for breakfast and could be incrementally upgraded.
and like others pointed out that things heating vents look weak even by a 1980s computer.
The most overpriced gaming laptop on the market probably.
Take it from a guy who loves gaming laptops. Gaming laptops have always had bad price/performance ratios, but Razer has the worst by far(Out of Alienware, MSI, Clevo and Asus).
left hand for wasd, right hand for mouse. unless gamers have 3 or more hands, the switchblade is useless.
I don't understand the term "Gaming Laptop".
Just went to look up this laptop and I love how they never show the underside of these laptops on the main website. smghottie made a valid point; pc gamers need to know first hand how well does this laptop's vent system operate under heavy gaming. I did a little background check on google and found these pics:
If that's the vent system for the fans, then, even with decent coolers like Cooler Master Storm Cooling Pad, NZXT Cryo LX laptop cooler etc., this laptop will have a high probability of overheating. And that probability isn't worth risking $2000+.
It's about time companies who make these products explain important issues like how well their laptop can game under pressure without overheating rather than "Look at my new laptop!!! It has a touch screen and colorful keys!!! Oh did I forget to mention that it has A TOUCHSCREEN?!?!?"
more ways to confusions now
Certainly not the World's first gaming laptop. I wonder, how well does it dissipate heat? That's the biggest issue w/ gaming laptops in my experience. Even pricey models get loud when games are running full-blast. It's too difficult to dissipate heat with traditional fans and I think w/ a 660 and Quad-Core you'd be hardpressed to keep it cool and comfortable. That digital screen by the keyboard is also quite stupid, and in about two years either won't work, won't look good, or both.
They should hire me to design a total new line of products that rocks ...
I'm looking for a coder-gamer keyboard + mouse ... i've seen almost all keyboards models over the internet and could not find anything better that a ms confort curve keyboard 2000 and a logitech g500 ......
I bet it's unusable because of the keyboard. Seriously, don't mess with your main method of input. People pass on keyboards just because the enter key is too big or the backspace key is too small... these guys are shrinking the entire keyboard. I can't even find a use for G-keys, let alone whatever that thing is on the right. They should've put that crap on the right as a separate USB device. The laptop looks like it has enough ports for an accessory like that.
Earlier model*
@yellowedd You're right, I was looking at the Cnet review of the model.
I Need to buy new laptop how much this ?
This laptop goes for over 2k, yet the Lenovo Ideapad y570 is going for $650 and has the same graphics card: NVIDIA GeForce GT 555M
I like how Min threw Valve in there - hint hint.
Logitech is probably the largest provider of PC and gaming accessories.
You might be surprised, go check out the top brand of alien ware gaming laptops cpu is 4.1 vs 4.2
@AlphaWolF_J Gaming and laptops mix just fine. I have a $600 HP m6 with 8 gigs of RAM, an AMD A-10 processor and an ATI Radeon 7660G graphics card, and it certainly more than gets the job done. Am I running everything on Ultra pushing an ungodly amount of frames? No. Am I running things on High to Medium and getting 60? Yes. Some people, like myself are forced to get laptops, for things like college. And when Dad's paying, you go to Best Buy and do the best you can.
@AlphaWolF_J People like you should stop comparing laptops to desktop PCs, they are not the same. It's like comparing a house to a motor-home. Don't be a moron. And why don't laptops and games mix? most idiotic statement I've ever seen.
@BimboShaggins still, probably one of the, if not the best windows-based gaming laptops.
Then google it.
@MaddenBowler10 This laptop has a GT660M graphics card which is much better than the 555M.
@Sndewey @AlphaWolF_J Alienware laptops are just overpriced piece of crap. They are like apple of gaming laptops.
@Sndewey @AlphaWolF_J I think the best bet for a decent gaming laptop is the lenovo y580. here are some specs:
i7, 8gb, GTX660M (same as Razer Blade), 1080p Screen. All for about 1K USD. If you want more options, CYberPower PC is a goo dplace to look as well.
Alienware is overpriced as are most of the gaming-PC builders that have been around (Alieanware, Falcon NW, etc.).
@Jakes0707 @AlphaWolF_J Way to be closed-minded (you've insulted several of the users here in the comments including AlphaWolf for having an opinion).
Yes, game and laptops can mix, but I think we can agree that there is a premium one pays in terms of cost and performance when choosing to go mobile. And why not compare desktops and laptops? Laptops aim to deliver desktop performance on the go and the development of technologies in laptops follow the same architectures as those for desktops. Not like comparing home and motor-homes at all (motorhomes have an automotive component as well; not portable in the same sense).
You should really consider desktops over laptops for gaming unless you absolutely must have games on the move (cheaper to spend 800 on gaming desktop and 500 on laptop for work than 2K for a gaming laptop of the same performance with poor battery life).
@yellowedd @MaddenBowler10 Lenovo Y580 has been on promotion for a total of 1.5 months this past 2 months and that's $849, oh and that has a GTX 660m and a quad core.
@SipahSalar @Sndewey @AlphaWolF_J
I know they are overpriced i just said that the best laptops are just behind the best desktops
How am I closed-minded? I'm not the one who shouted "Laptops and gaming DO NOT MIX". And it seems you don't understand the analogy I was trying to convey, so take some time to think about it. Motor-homes were DESIGNED to be portable/on the road (literally), the same can be said with laptops. I know you can carry your massive PC, and its screen, and keyboard, and mouse...but then if you were to do that on a regular basis a laptop would be best, would it not? You can't very well fit a giant fridge into your motor-home but you can in your house. The same with desktop PCs and laptop. Because of there size and design, desktops can be upgraded with massive graphics cards, etc. while laptops are very limited in their size.
@yellowedd @MaddenBowler10 To add to that (sorry) you could get a Clevo P150em w/ a 7970m( which is a desktop 7870 but 15% slower clocks at stock) and a 3610qm quad core for about $1400 while the GTX 660m is just a desktop GT 640 w/ slower clocks.