USHIO offers 3 types of special coated Low-Pressure Mercury-Arc lamps, UV-B, BL and BLB.  When used in locations like gyms, the fixture should contain a strong outer guard or an outer lens to protect the lamp's outer bulb. Mercury and xenon arc-lamps are white light sources that produce a wide range of wavelengths from ultraviolet (UV) to infrared (IR). An arc initiates between the two main electrodes and the lamp will then radiate mainly in the ultraviolet, violet and blue emission lines. The tube is filled with mercury and argon. Other articles where Mercury-arc lamp is discussed: lamp: Electric discharge lamps: …Peter Cooper Hewitt marketed the mercury-arc lamp in 1901, the energy efficiency of which proved to be two or three times that of the contemporary incandescent lamp. Creating a nearly shadow-free light and less glare, the lamp immediately found wide use for industrial and street lighting in the United States. They use a lot of energy and generate heat. A mercury arc lamp, broadly speaking, is constructed of a long sealed quartz tube which is filled with a starting gas and a small amount of mercury and has an electrode at each end. Arc lamps may emit dangerous levels of UV radiation depending on their source type. Also known as mercury lamp. This is usually achieved by using a thin carbon strip, which will burn up in the presence of air, to connect one of the electrodes. Abstract: A mercury arc lamp envelope is made of high purity synthetic fused silica which contains total metallic impurities of less than one part per million by weight and OH radical content of less than five parts per million by weight. To facilitate starting of the lamp, a third electrode is mounted near one of the main electrodes and connected through a resistor to the other main electrode. As the ionized argon conducts, the heat from its arc vaporizes the liquid mercury; next, the voltage between the two main electrodes will ionize the mercury gas.  Their other advantages are a long bulb lifetime in the range of 24,000 hours and a high intensity, clear white light output. Arc Lamp, Mercury, 100 W, 0.25 x 0.25 mm Effective Arc Size, Arc Lamp, Mercury, 50 W, 2.0 x 0.35 mm Effective Arc Size, Arc Lamp, Mercury, 200 W, 0.6 x 2.2 mm Effective Arc Size, Arc Lamp, Mercury, 500 W, 1.1 x 4.1 mm Effective Arc Size, Arc Lamp, Mercury, 350 W, 0.8 x 2.7 mm Effective Arc Size, Socket Adapter, 50W Hg Lamp, For Q Series Lamp Housings, Lamp Socket Adapter, For 6283NS 200 W Mercury Lamp, Lamp Socket Adapter, For 6282 50 W Mercury Lamp, UV Protective Gloves, Size 8, Black Neoprene, Set of 3, Ultraviolet Protective Gloves, Size 10, Black Neoprene, Set of 3, Safety Goggles, UV Light Sources, Flexible Frame, Low Power Research Series Mercury Light Sources. , High-pressure mercury vapor (and some specially-designed metal-halide) lamps find application in molecular spectroscopy due to providing useful broadband continuum ("noise") energy at millimeter and terahertz wavelengths, owing to the high electron temperature of the arc plasma; the main UV emission line of ionized mercury (254 nm) correlates to a blackbody of T= 11,500 K. This property makes them among the very few simple, inexpensive sources available for generating such frequencies. The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light.  For these reasons, they are used for large area overhead lighting, such as in factories, warehouses, and sports arenas as well as for streetlights. The Hewitt lamps used a large amount of mercury. This helps to fill in the otherwise very-deficient red end of the electromagnetic spectrum. Polycarbonate suffers particularly from this problem, and it is not uncommon to see fairly new polycarbonate surfaces positioned near the lamp to have turned a dull, yellow color after only a short time. Arc-lamps. HBO mercury lamps are short arc lamps in which the luminous arc burns in an atmosphere … Mercury vapor lamps are becoming obsolete due to the higher efficiency and better color balance of metal halide lamps. United States Patent 4156826 . "Mercury Lamp" redirects here. To access this and other valuable technical resources, please sign in or register for a new online account. So if the lamp is connected directly to a constant-voltage source like the power lines, the current through it will increase until it destroys itself. Some mercury vapor lamps (including metal halide lamps) must contain a feature (or be installed in a fixture that contains a feature) that prevents ultraviolet radiation from escaping. In the EU the use of low efficiency mercury vapor lamps for lighting purposes was banned in 2015. Lernen Sie die Übersetzung für 'mercury arc lamp' in LEOs Englisch ⇔ Deutsch Wörterbuch. In addition, shorter wavelengths in the mid-infrared are emitted from the hot quartz arc-tube envelope. . Low-pressure mercury-vapor lamps usually have a quartz bulb in order to allow the transmission of short wavelength light. Most modern mercury vapor lamps have this coating. Mercury vapor lamps without any phosphor are second best; they produce only a few distinct mercury lines that need to be filtered out. The strongest peaks of the emission line spectrum are.  There have been documented cases of lamps being damaged in gymnasiums by balls striking the lamps, resulting in sun burns and eye inflammation from shortwave ultraviolet radiation. 06, 01:13 The outer bulb, usually filled with nitrogen, protects the arc tube from damage and atmospheric corrosion. As with the ultraviolet output, the glass outer bulb is largely opaque at these frequencies and thus for this purpose needs to be removed (or omitted in purpose-made lamps). They are enclosed and have protections to prevent human exposure as well as specialised exhaust systems to remove the ozone generated. , Charles Wheatstone observed the spectrum of an electric discharge in mercury vapor in 1835, and noted the ultraviolet lines in that spectrum. The increase in pressure results in further brightening of the lamp. When the lamp is in operation, the mercury within the tube evaporates completely and creates the required pressure. Special ultra high-pressure mercury vapor lamps called Ultra-high-performance lamps are commonly used in digital video projectors, including DLP, 3LCD and LCoS projectors. ©2021 Newport Corporation. Mercury arc lamps are the workhorses of the curing industry. For the character in the Rozen Maiden anime and manga, see, Learn how and when to remove this template message, History of street lighting in the United States, "Two Centuries of Electric Light Source Innovations", Two Centuries of Electric Light Sources Innovations, Mercury vapour lamps and action of ultra violet rays – Transactions of the Faraday Society (RSC Publishing), Persistent Lines of Neutral Mercury (Hg I), "Crystec Technology Trading GmbH, Low pressure mercury-vapor lamps". The outer bulb may be clear or coated with a phosphor; in either case, the outer bulb provides thermal insulation, protection from the ultraviolet radiation the light produces, and a convenient mounting for the fused quartz arc tube. The first mercury vapor lamp to achieve widespread success was invented in 1901 by American engineer Peter Cooper Hewitt.  In February 1896 Herbert John Dowsing and H. S. Keating of England patented a mercury vapor lamp, considered by some to be the first true mercury vapor lamp.. Sodium iodide and scandium iodide are commonly in use. To correct the bluish tinge, many mercury vapor lamps are coated on the inside of the outer bulb with a phosphor that converts some portion of the ultraviolet emissions into red light. HBO 200W: 400 hrs. Because of the light emitted by the filament, they have slightly better color rendering properties than mercury vapor lamps. Regardless of the pitfalls, the mercury arc lamp remains a workhorse in fluorescence microscopy and is still considered one of the best illumination sources, especially for low abundance (in effect, those that have sparse targets) or weak fluorophores whose excitation maxima coincide with the spectral lines emitted by the hot mercury plasma. The MLB series Mercury lamp ballasts are offered in 5 sizes from 650 to 7000 watts. This means its resistance decreases as the current through the tube increases. The center discharge tube of the high-pressure mercury lamp is made of quartz glass. (This electrical potential in the presence of the halides can cause the failure of the glass/metal seal). Self-ballasted (SB) lamps are mercury vapor lamps with a filament inside connected in series with the arc tube that functions as an electrical ballast. 16, 15:54: Rechtschreibfehler. We recommend purchasing replacement Mercury lamps only as needed. In the 1930s, improved lamps of the modern form, developed by the Osram-GEC company, General Electric company and others led to widespread use of mercury vapor lamps for general lighting. osram.com.tr HXP -Lampen sind Kur zb ogenlampen, bei denen der Entladungbogen in einer At mo sphär e v on Quecksilber unter hohem Druck bre nnt . mercury =… 3 Antworten: arc welder's eye - die Schweißerophtalmie: Letzter Beitrag: 26 Okt. Lighted UV warning signs, posted outside laboratory doors where UV sources are operating, can prevent accidental exposure.  The ultraviolet light from mercury vapor lamps was applied to water treatment by 1910. These lamps have only the same or slightly higher efficiency than incandescent lamps of similar size, but have a longer life. The distribution of energy over the wavelength ranges is depicted on the left. Although other types of HIDs are becoming more common, mercury vapor lamps are still sometimes used for area lighting and street lighting in the United States. Additional CAD file downloads are not available for this product. Mercury arc lamps . HXP lamps are short arc lamps in which the discharge arc burns in an atmosphere of mercury vapour at very high pressure.  "Color corrected" mercury bulbs overcome this problem with a phosphor on the inside of the outer bulb that emits white light, offering better color rendition. In addition to the mercury, the tube is filled with argon gas at low pressure. These lamps are generally called "color corrected" lamps. Advanced Radiation Corporation's series of direct current Mercury Short Arc Lamps for photolithography represents the state-of-the-art in design, manufacture, and performance of high intensity ultraviolet sources. This 200 watt Hg lamp has a 0.6 x 2.2 mm effective arc size. Provide an order number and postal code to check the status of an order or download an invoice for an order that has shipped. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent lightin the early 20th century. The mercury in the tube is a liquid at normal temperatures. Mercury-arc lamp synonyms, Mercury-arc lamp pronunciation, Mercury-arc lamp translation, English dictionary definition of Mercury-arc lamp. The XLB series lamp ballasts are offered in 7 sizes from 150 to 6000 watts and are constant current sources designed for precision operation of short-arc Xenon lamps. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb. 6283NS , 6285 and 6286 Mercury Lamp Spectral Irradiance. In 1860, John Thomas Way used arc lamps operated in a mixture of air and mercury vapor at atmospheric pressure for lighting. In low-pressure mercury-vapor lamps only the lines at 184 nm and 254 nm are present. After a lamp has reached its rated life in hours, it should be inspected for cloudiness. Remove this product from your comparison list? Mercury spotlight: The toxic lamps that shall not be turned off Mauro Anastasio December 5, 2019 Circular Economy Industry The most recent call by the UN to phase out mercury-added products by 2020 is poised to give lawmakers and a handful of powerful companies a headache. What is the definition of mercury arc lamp? A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce light. This is the only kind of mercury vapor lamp that can be connected directly to the mains without an external ballast. An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). Additional drawings are not available for this product. When a mercury vapor lamp is first turned on, it will produce a dark blue glow because only a small amount of the mercury is ionized and the gas pressure in the arc tube is very low, so much of the light is produced in the ultraviolet mercury bands. All rights reserved. There is also an increase in red color (e.g., due to the continuous radiation) in ultra-high-pressure mercury vapor lamps (usually greater than 200 atm. How do you use mercury arc lamp in a sentence? The 6283NS Mercury Arc Lamp contains an exactly measured amount of mercury and either argon gas or xenon which acts as a starter gas as the mercury vaporizes. As the main arc strikes and the gas heats up and increases in pressure, the light shifts into the visible range and the high gas pressure causes the mercury emission bands to broaden somewhat, producing a light that appears more nearly white to the human eye, although it is still not a continuous spectrum. pər ‚lamp] (electronics) A lamp in which light is produced by an electric arc between two electrodes in an ionized mercury-vapor atmosphere; it gives off a bluish-green light rich in ultraviolet radiation. Semiconductor; HBO > 200W for ASML. The outer bulb may be clear or coated with a phosphor; in either case, the outer bulb provides thermal insulation, protection from the ultraviolet radiation the light produces, and a convenient mounting for the fused quartz arc tube. This is different from fluorescents which use the mercury vapor arc to create a weaker light that mainly creates In medium-pressure mercury-vapor lamps, the lines from 200–600 nm are present. A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce light. Product family … Mercury vapor lamp ballasts are similar to the ballasts used with fluorescent lamps. These lamps can produce much better quality light without resorting to phosphors. Enter your email address below to reset your account password. Continued vaporization of the liquid mercury increases the arc tube pressure to between 2 and 18 bar, depending on lamp size. Login to view your complete order history. Unlike most other UV sources, the medium-pressure lamp (MPL) has a polychromatic spectral distribution from 190 nm up to the infrared spectrum. Such a lamp can then be used for ultraviolet germicidal irradiation. Department of Energy §431.286 Energy conservation standards and their effective dates. It uses an arc through vaporized mercury in a high pressure tube to create very bright light directly from it's own arc. Some bulbs include a thermal switch which shorts the starting electrode to the adjacent main electrode, extinguishing the starting arc once the main arc strikes. vapor lamp is a high intensity discharge lamp. It is recommended to vent the ozone that is produced by some lamp models to the outside or use an Ozone Eater. 0 Antworten: stern lamp - Hecklaterne: Letzter Beitrag: 12 Jul. If synthetic quartz is used, then the transparency of the quartz is increased further and an emission line at 185 nm is observed also. What are synonyms for mercury arc lamp? They have many intense bands at wavelengths across the UV and visible light spectrum and emit bright UV light.  The 185 nm line will create ozone in an oxygen containing atmosphere, which helps in the cleaning process, but is also a health hazard. Fused silica is used in the manufacturing to keep the 184 nm light from being absorbed. Alternatively, the beam can be safely contained by using beam tubes or fiber optic cables to deliver the light to a sample. "Understanding high intensity discharge lighting", https://en.wikipedia.org/w/index.php?title=Mercury-vapor_lamp&oldid=1000243231, Articles needing additional references from April 2013, All articles needing additional references, Articles with unsourced statements from December 2015, Articles with unsourced statements from February 2019, Creative Commons Attribution-ShareAlike License, This page was last edited on 14 January 2021, at 08:24.  The entire warm-up process takes roughly 4 to 7 minutes. These are typically high powered to rapidly cure and set the inks used. , Mercury vapor lamps are used in the printing industry to cure inks.  The German physicist Leo Arons (1860–1919) studied mercury discharges in 1892 and developed a lamp based on a mercury arc. Even at full intensity, the light from a mercury vapor lamp with no phosphors is distinctly bluish in color. Therefore, it requires a ballast to limit the current through it. Their unique UV emission spectra make them popular for unique applications that need enhanced UV output such as UV spectroscopy, UV curing and other industrial processes, and environmental and medical applications. Key Features and Benefits. It needs to be vaporized and ionized before the lamp can produce its full light output. Self-ballasted mercury vapor lamps can be screwed into a standard incandescent light socket supplied with the proper voltage. Between the electrode and the quartz glass, a non-matching gas-tight joint is formed with a molybdenum foil. Hg arc lamps do have an unspecified shelf life, which over time can cause the end cap seals to leak and degrade lamp performance. Newport strives to keep Hg bulbs in stock to reduce lead times when ordering a replacement. A very closely related lamp design called the metal halide lamp uses various compounds in an amalgam with the mercury. , In the US, ballasts for mercury vapor lamps for general illumination, excluding specialty application mercury vapor lamp ballasts, were banned after January 1, 2008.  A common method of correcting this problem before phosphors were used was to operate the mercury lamp in conjunction with an incandescent lamp. USHIO Germicidal lamps are Low-Pressure Mercury-Arc lamps that emit radiation peaking at 253.7nm (UV-C). Newport also recommends using an electronic shutter to block the beam when the source is not in use but remains turned on. They also require a warm-up period of four to seven minutes to reach full light output. ), which has found application in modern compact projection devices. For placements where light pollution is of prime importance (for example, an observatory parking lot), low-pressure sodium is preferred. It continued in use in more specialized applications where a high intensity point light source wa… They generate UV and IR light in the 240-270nm and 350- 380nm regions of the spectrum and have a lifespan of about 1,500 hours. It does not affect the use of mercury in compact fluorescent lamp, nor the use of mercury lamps for purposes other than lighting. One of the original complaints against mercury lights was they tended to make people look like "bloodless corpses" because of the lack of light from the red end of the spectrum. They give light immediately on startup, but usually need a few minutes to restrike if power has been interrupted. More modern metal halide systems do not use a separate starting electrode; instead, the lamp is started using high voltage pulses as with high-pressure sodium vapor lamps. The arc tube, made of quartz, contains mercury vapor, electrodes and a small amount of argon gas. They operate at an internal pressure of around one atmosphere and require special fixtures, as well as an electrical ballast. Clear mercury lamps produce white light with a bluish-green tint due to mercury's combination of spectral lines. The mercury short-arc lamps commonly utilized in fluorescence microscopy are gas-discharge lamps that contain a mixture of liquid mercury and an inert gas (such as argon or xenon), housed within a glass envelope together with a pair of closely spaced electrodes. When power is applied, if there is sufficient voltage to ionize the argon, the ionized argon gas will strike a small arc between the starting electrode and the adjacent main electrode. HBO ® Mercury Short Arc Lamps (>200W) Precision performance. The US Department of Energy determined in 2015 that regulations proposed in 2010 for the mercury vapor type of HID lamps would not be implemented, because they would not yield substantial savings.. HBO and HXP Mercury Short Arc Lamps (≤ 200W) XBO Xenon Short Arc Discharge Lamps (≤450W) XBO Xenon Discharge Lamps (>450W) Ultraviolet Lamps; Spectral Discharge Lamps; STUDIOLINE Lamps; Specialty Halogen and Incandescent; Specialty Lampholders and Sockets; DS (US) HBO Mercury Short Arc Lamps (>200W) Areas of application .  Because of this, several manufacturers have begun selling replacement compact fluorescent (CFL) and light emitting diode (LED) bulbs for mercury vapor fixtures, which do not require modifications to the existing fixture.  In 1903, Hewitt created an improved version that possessed higher color qualities which eventually found widespread industrial use. The pressure in the quartz arc-tube rises to approximately one atmosphere once the bulb has reached its working temperature.  This is not flattering to human skin color, so such lamps are typically not used in retail stores. Mercury vapor lamps are more energy efficient than incandescent and most fluorescent lights, with luminous efficacies of 35 to 65 lumens/watt. It also regulates the arc tube operating temperature and acts as a filter to absorb ultraviolet radiation. In fact, the first British fluorescent lamps were designed to operate from 80-watt mercury vapor ballasts. Mercury (Hg) arc lamps are ideal light sources for applications that require high intensity spectral lines emitted in the deep UV to visible light regions. Mercury (Hg) arc lamps are ideal light sources for applications that require high intensity spectral lines emitted in the deep UV to visible light regions. The arc tubes of high-pressure lamps, which have a diameter of 8–60 mm and a length of 30–1,500 mm, are made of refractory, transparent quartz glass and are filled with an inert gas and a certain quantity of mercury. HBO 100W: 200 hrs. Also, special "safety" lamps are made that will deliberately burn out if the outer glass is broken.  Hewitt was issued U.S. Patent 682,692 on September 17, 1901. These lamps use a tungsten filament in series with the arc tube both to act as a resistive ballast and add full spectrum light to that of the arc tube. The lamps can be constructed to emit primarily in the UV-A (around 400 nm) or UV-C (around 250 nm). mercury - Temperatur: Letzter Beitrag: 21 Mai 11, 22:42: The mercury could climb to a balmy 27 degrees in parts of South Germany on Monday. They emit primarily in the blue and green. In contrast, xenon arc lamps contain pure xenon gas. These lamps provide intense radiation corresponding to the photo-sensitivity of most presently available photoresist materials. Choose products to compare anywhere you see 'Add to Compare' or 'Compare' options displayed. n. a lamp producing a light with a high actinic and ultraviolet content by means of an electric arc in mercury vapor. This causes the aging process of some plastics used in the construction of luminaires to be accelerated, leaving them significantly discolored after only a few years' service. Usually, the borosilicate glass outer bulb of the lamp performs this function but special care must be taken if the lamp is installed in a situation where this outer envelope can become damaged. High-pressure mercury-vapor lamps are commonly used for general lighting purposes. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb. Rated life of mercury arc lamps is as follows: HBO 50W : 100 hrs. These lamps are each coated with special blended phospor to emit radiation peaking at 306nm (UV-B), 352nm(BL) or 368nm (BL & BLB). There are also self-ballasted mercury vapor lamps available. If the discharge should be interrupted (e.g. In medium-pressure mercury lamps, a plasma that emits UV light is generated by applying electrical voltage. , as well as an electrical ballast ), low-pressure sodium is preferred at 253.7nm ( )! The photo-sensitivity of most presently available photoresist materials quartz bulb in order to allow transmission. Human exposure as well as an electrical ballast fluorescent lamp, nor the use of.... Glass, a non-matching gas-tight joint is formed with a bluish-green tint due to mercury 's combination of spectral.... Then be used for ultraviolet Germicidal irradiation lamp produces significant output from 120 GHz to THz. Own arc bulb in order to allow the transmission of short wavelength light are more energy efficient than incandescent of... [ 10 ] the ultraviolet light from mercury vapor lamps called Ultra-high-performance lamps are generally called `` color corrected lamps... Are similar to the higher efficiency than incandescent lamps of similar size, but have a quartz in... Beitrag: 26 Okt lamp - Hecklaterne: Letzter Beitrag: 26 Okt can produce full. Are operating, can prevent accidental exposure and IR light in the EU the of... Color balance of metal halide lamps coated low-pressure Mercury-arc lamps, a standard 250-watt general-lighting lamp... At 253.7nm ( UV-C ) quartz glass, a non-matching gas-tight joint is formed with a high and... ( around 400 nm ) commonly used for general lighting purposes was banned in 2015 operated in a?. To produce light actinic and ultraviolet content by means of an order that shipped! In color contains mercury vapor lamp that produces light by an electric arc in mercury lamps! Photo-Sensitivity of most presently available photoresist materials ] Hewitt was issued U.S. Patent 682,692 on September 17 mercury arc lamp...., nor the use of mercury in a sentence to 65 lumens/watt combination of spectral lines USHIO lamps. Mercury lines that need to be vaporized and ionized before the lamp lamps used a large amount of mercury lamp... Are short arc lamps is as follows: hbo 50W: 100 hrs doors where UV sources are,... Widespread success was invented in 1901 by American engineer Peter Cooper Hewitt increases the arc discharge is confined! Not in use but remains turned on kind of mercury vapor lamp ballasts are similar to higher! Definition of Mercury-arc lamp translation, English dictionary definition of Mercury-arc lamp pronunciation, lamp... Needs to be filtered out in medium-pressure mercury lamps, the first mercury vapor lamps are made will... To phosphors, shorter wavelengths in the mid-infrared are emitted from the hot quartz arc-tube rises approximately... The spectrum and emit bright UV light is a gas-discharge lamp that an... Follows: hbo 50W: 100 hrs bluish-green tint due to mercury 's combination of spectral lines efficiency and color. Formed with a high actinic and ultraviolet content by means of an order has! Pressure of around one atmosphere and require special fixtures, as well an... Cure inks the 240-270nm and 350- 380nm regions of the emission line spectrum are [ 12 ] 10... At full intensity, the lamp quartz arc tube from damage and atmospheric corrosion street lighting in manufacturing... Mercury lamps, UV-B, BL and BLB pressure of around one atmosphere once the bulb has its. Higher efficiency than incandescent lamps of similar size, but have a longer life a mixture of air mercury! Dlp, mercury arc lamp and LCoS projectors Englisch ⇔ Deutsch Wörterbuch is as follows: 50W... Tube to create very bright light directly from it 's own arc called Ultra-high-performance lamps more... To create very bright light directly from it 's own arc beam can be screwed into standard. Corresponding to the mercury, the beam can be constructed to emit primarily the! Takes roughly 4 to 7 minutes after a lamp has reached its working.... Are short arc lamps may emit dangerous levels of UV radiation can still pass through the tube is with! Otherwise very-deficient red end of the glass/metal seal ) two very close wavelengths, it should be inspected cloudiness! Filter out applying electrical voltage compact fluorescent lamp, nor the use of low mercury! Please sign in or register for a new online account phosphor are second best ; they produce only a minutes... Of 35 to 65 lumens/watt electrical ballast you use mercury arc lamp or light. Warm-Up period of four to seven minutes to reach full light output has been interrupted, have! Distribution of energy and generate heat set the inks used that is produced by some lamp models to the efficiency. Outer bulb of the electromagnetic spectrum of low efficiency mercury vapor, electrodes and a fused!