Discharge lamp

Discharge lamp - lighting device, the principle of action is based on the burning of an arc of ionized gas. This is a vast family that at the beginning of the XXI century captured almost three-quarters of the illumination segment in the world. This includes the popular fluorescent fluorescent lamps, lamps DRL.Even before the introduction into use of lighting devices operating at the expense of the gas discharge, are found in the novel by Jules Verne, "Journey to the Center of the Earth"( 1864).

History of the development of electrostatic ionization of gasesTo readers presented the phenomenon, you need to take into account the peculiarities of the design. In the mercury barometer there is a tube, sealed from the end. In addition, there is a bowl. Both items are filled with metallic mercury.

To determine the pressure, the tube is sharply turned over and lowered into the bowl. Then mercury under the influence of earthly force flows down, forming a vacuum above itself. As a result, the sealed end of the tube remains hollow, and the length of the empty space depends on the atmospheric pressure, which, acting on mercury in the bowl, is designed to balance the force of gravity.

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Picard Barometer

When transporting the Barometer, Picard hurried and shook the device. As a result, glass was electrified by friction with mercury, and a static charge caused the ionization of metallic vapors. The process was greatly facilitated by the vacuum created. Mercury vapors and today are used in separate gas-discharge light sources. For example, the ultraviolet component of the glow activates fluorescent lamp phosphor.

Picard could not explain the detected phenomenon, but immediately reported on what happened in scientific circles. Later, the study engaged the famous Swiss mathematician Johann Bernoulli. The task turned out to be too hard for him, but this scholar actively practiced the experience with a glow, gave an idea to the French Academy of Sciences. In 1700, a British mechanic, part-time scientist, Francis Hoxby, saw a phenomenon at the demonstration. On the basis of the Royal Scientific Society of Britain, Hawksby is actively engaged in experiments.

As a basis for the decisive experiment, Hawksby takes the model of Gericke's electrostatic generator( 1660).According to the descriptions of the machine was a solid ball of sulfur, rotating on an iron rod. With the friction of the operator’s palm, the object acquired a significant charge during rotation. The further course of the thoughts of Hoxby is clear. Guericke’s instruction contained a proposal to pour sulfur into a glass ball, then break it. English scientist missed the specified step. Unfortunately, it is not known whether the earlier works( for example, the treatise of Hilbert in 1600) had an idea about the electrification of glass, but Hoxby put forward an appropriate assumption.

Gericke electrostatic generator model

As a result, the experimental set-up contained instead of a sulfur ball a glass with drops of mercury at the bottom, and a vacuum was created inside if possible. When the sphere rotated on the iron rod and electrified by rubbing with palms, a luminescence was observed to read the book in close proximity. In 1705, the English Scientific Society demonstrated the first gas-discharge lamp. The correct explanation was provided that mercury vapor was involved in the detected phenomenon. Then - the course of work stopped for a century. There was no practical application of the newly discovered phenomenon.

The first gas-discharge lamps

It cannot be said that the 18th century was useless for research in the field of electricity, despite the phrase dropped above. Significant are the works of Dufet, in 1733, who suggested the presence of two kinds of charges for the purpose of theoretical substantiation of the observed phenomenon. He called them pitch and glass. This is an explanation of the phenomenon considered by Gilbert in 1600:

1. An electrified ball attracts bodies.
2. Having touched the ball, the bodies start to push off from the object.

In Dufet's understanding, an object acquired a charge of a similar sign upon contact. What explains the phenomenon. But true progress in science began when states abolished the punishment for practicing witchcraft. As a result, the Leiden Bank was born, and Benjamin Franklin proved the electrical nature of lightning, Volta invented the first electrochemical source of energy. In 1729, a revolutionary discovery took place, which became the basis for others: Stephen Gray thought of putting the conductors together and got the world's first electrical circuit. Since then, the current began to transmit over a distance.

Invented in 1746 by William Watson, an electric machine fused a charge on silk cords, which allowed Jean-Antoine Nollet to demonstrate a spectacular arc in a discharged gas medium. At the point of Gottfried, Grummert suggested that such lighting would be suitable for use in mines and places where an open flame increases the likelihood of an explosion. Johann Winkler noted that it’s not bad to use long flasks bent in the shape of the letters of the alphabet instead of balls, anticipating the appearance of the Heusler tubes and the TV screen.

A little later, in 1752, Watson partially implemented these ideas( the first display was patented in 1893).For example, demonstrating experience with arc burning in a tube with a length of 32 inches. Thanks to such brilliant discoveries, in 1802 two events immediately significant for the topic under consideration occurred:

• The Englishman Humphrey Davy discovered the phenomenon of glow of platinum wire heated with electricity.
• Our compatriot, V. Petrov with the help of a voltaic column consisting of 4200( according to other data - 2100) pairs of copper and zinc plates. For comparison, the energy source of Sir Humphry Davy showed twice as little power( 2000 plates).

Petrov's achievements were forgotten under the influence of the events of the Patriotic War of 1812 and by virtue of Russian spit. In England, electricity was approached seriously. The merit of Humphrey Davy is considerable. He, being a chemist, repeating the experiments of a foreign colleague, began experimenting with various gas media. Of course, a member of the Royal Scientific Society was familiar with the experiences of Francis Hawksby and wanted to check whether a new discovery had become a repetition of early attempts to create artificial sources of light.

The experiments of Francis Hawksby

These experiments led to the discovery of linear spectra of gas discharges. Along the way, Wollaston and Fraunhofer noticed the features of solar radiation that later allowed Kirchhoff and Bunsen to make assumptions about the composition of the solar atmosphere. It is closely connected with the topic under consideration, the discharge spectrum is also ruled. For example, sodium lamps give orange light, and with the help of the phosphor it is necessary to adjust the frequency distribution( DRL lamps).Then Michael Faraday took the baton( from the mid 30s of the XIX century), showed the process of arcing in the environment of rarefied gases. Heinrich Rumkorf also made a contribution, having provided a physicist with a tool for obtaining high voltage pulses( Rumkorf coil, 1851).In 1835, Charles Wheatstone registered the spectrum of the arc discharge in mercury vapor, incidentally noting the ultraviolet component.

Heusler Discharge Lamps

Heusler's creations are considered the first commercially successful. The date of birth is considered to be 1857.The aforementioned glassblower and part-time physicist guessed to insert 2 electrodes into a flask with a discharged gas. Feeding on them the voltage of the arc was seen. Geisler connected together the discoveries of Petrov and Hawksby. The arc smolders in the flask with the atmosphere of gas vapors. And further - the choice of color - is not difficult, based on the developments of Sir Humphrey Davy and Michael Faraday.

Since the 1980s, Heusler tubes have been widely produced for the entertainment purposes of the population. Today, neon lights are considered the face of the United States. It is noteworthy that being placed near sources of strong electromagnetic radiation - Tesla coils - Heusler lamps light up spontaneously. The conditions for ionization of the rarefied gas medium are fulfilled. Research associated with the search for technical solutions for lighting led scientists to the discovery of an electron, the measurement of its charge and mass, the emergence of light tubes.

Lamp Geisler

Meanwhile in Russia

The possibility of igniting a powder charge by an electric spark has been known since about 1745.But the sapper could hardly carry the Leyden jar or patiently rub amber with wool in any weather conditions. For a long time, military affairs did not take into account such trifles. In 1812, Russian officer Shilling was able to produce an underwater explosion through an electric battery. It is believed that military affairs gave impetus to the development of research in electricity in Russia. The first arc lamp was installed in 1849 by the inventor( Jacobi) on the tower of the Admiralty of St. Petersburg. Her light turned out to be so bright that it was compared to the average man and the sun.

The use of spotlights with discharge lamps is limited to military affairs, with a few exceptions, when sources point the way to ships from a beacon. We are interested in the work of John Thomas Ray, dated 1860, who guessed to combine the electric arc( Petrov and Jacobi) with the atmosphere of mercury vapor( Michael Faraday) at normal pressure.

From Edison to modern gas-discharge lamps

Despite clear advantages, the Heusler gas-discharge lamps showed significant drawbacks. For example, a small service life. From the 90s of the 19th century, one Daniel McFarlen Moore worked for Edison’s company and soon after entering the service he began to study history. He was interested in Heusler gas discharge lamps. What is wrong with my light? Asked Edison. Moore replied: he is too dull, too hot and too red. This is the whole truth about the incandescent bulbs of that time.

Modern lamp

In 1892, the mercury discharge lamp was improved by Martin Leo Arons. The development in 1901 was improved by Peter Cooper Hewitt and gained commercial success.

Since 1894, Moore has organized two of his own companies dealing with lighting. The main feature of the lamps( 1896) was that the gas was resumed as it was consumed. As a result, the device worked indefinitely. The first commercial use was registered in 1904.A lamp with a return of 10 lumens per 1 W illuminated the hardware and appliances shop. As eyewitnesses wrote, despite the complexity and bulkiness( 50 yards in length), the return was worth it. The efficiency of new gas-discharge lamps was 3 times higher than the similar figures for incandescent lamps.

A distinctive feature was the use of nitrogen and carbon dioxide vapors in Moore lamps. The result was daylight. A pair of nitrogen gave a soft glow and low color temperature. The advent of tungsten filaments made further production unprofitable, the companies were absorbed by General Electric( 1912), and the patents were bought up. But Moore did not remain without work, moving to the laboratories of his successor in the endless relay. Later invented the neon lamp.

Those who want to learn more can look at the sections on DRL lamps and fluorescent lamps.