Telegraph relays amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
This relay includes a marble base and was made by Charles T. Chester of New York City. The electromagnet coils are fixed but the steel core can be moved to adjust the strength of the magnetic field.
In 1907 Ohio janitor turned inventor James Murray Spangler developed a new type of electrical sweeper for cleaning carpets. Unable to finance large-scale manufacture of his invention, he turned to a local harness and leather goods maker, William H. Hoover, who established the Electric Suction Sweeper Company. In November 1908, Spangler filed for a US patent and almost a year later received patent number 935,558 that he assigned to Hoover’s new company. This 1908 Hoover vacuum cleaner shows the features seen in the patent: a fan to produce the vacuum and push air into a dust bag, rings on the bottom of the unit to keep the carpet from being pulled into the fan, and brushes driven by the same motor as the fan.
Several inventors developed mechanical carpet cleaners during the 19th century and Spangler’s design was not the first attempt to adapt electricity to this task. One of the major innovations that made Hoover successful lay in how he sold the machine. Hoover realized the value of free, in-home trials and live demonstrations by trained sales-people. Innovations in both technology and marketing combined to make the product successful.
Description: Tin housing, restored silver-colored bag and new wooden handle. "Hoover" lettered on front. Markings: "Trade Hoover mark (/) Suction Sweeper (/) Co. (/) New Berlin". Alternating current motor 110 volt 66 cycle. Reference: US Patent 935558, issued 28 September 1909 to James Murray Spangler, assigned to the Electric Suction Sweeper Co., of New Berlin, OH - later the Hoover Vacuum Co. of New Canton, OH.
Thomas Edison and others considered element number 6, carbon, ideal for lamp filaments in part because it has the highest melting point of any element. Element number 74, tungsten, has the next highest melting point but it then existed only as a powder. Attempts to make it into a workable form failed until early in the 1900s when a burst of invention occurred in Europe. A pressing technique called "sintering" (squeezing a material into a dense mass) was adopted by several inventors.
The most commercially successful design proved to be that of Dr. Alexander Just and Franz Hanaman of Austria. Their work on sintering tungsten was based on a prior sintering process developed by Carl Auer von Welsbach for his filament made of osmium. Just and Hanaman made a tungsten and organic paste, squirted it through a die, baked out the organic material, then sintered the tungsten in a mix of gasses. The resulting filament gave about 8 lumens per watt and lasted 800 hours.
Another Austrian, Dr. Hans Kutzel, used an electric arc to make a tungsten and water paste. He then pressed, baked, and sintered the tungsten in a manner similar to Just and Hanaman's procedure. Yet another pair of Austrians, Fritz Blau and Hermann Remane, adapted the osmium lamp process (they worked for Welsbach) by making a filament from an osmium and tungsten mix. They soon changed their "Osram" lamp filament to tungsten only. (The German word for tungsten is wolfram.)
All three filaments were brittle and collectively known as "non-ductile" filaments. Individual filaments could not be made long enough to give the proper electrical resistance, so lamps needed several filaments connected end-to-end. U.S. companies quickly licensed rights to all of the non-ductile patents. This particular lamp was made under license by General Electric and sent to the National Bureau of Standards for use as a standard lamp.
Lamp characteristics: Medium-screw base with glass insulator. Five single-arch tungsten filaments (in series) with 5 upper and 8 lower support hooks. The stem assembly features soldered connectors, Siemens-type press seal, and a cotton insulator. Tipped, straight-sided envelope with taper at neck.
Irving Langmuir received a Ph.D. in physical chemistry in 1906 from the University of Göttingen. He studied under Walther Nernst, who had invented a new type of incandescent lamp only a few years before. In 1909 Langmuir accepted a position at the General Electric Research Laboratory in Schenectady, New York. Ironically, he soon invented a lamp that made Nernst's lamp (and others) obsolete.
Langmuir experimented with the bendable tungsten wire developed by his colleague William Coolidge. He wanted to find a way to keep tungsten lamps from "blackening" or growing dim as the inside of the bulb became coated with tungsten evaporated from the filament. Though he did not solve this problem, he did create a coiled-tungsten filament mounted in a gas-filled lamp—a design still used today.
Up to that time all the air and other gasses were removed from lamps so the filaments could operate in a vacuum. Langmuir found that by putting nitrogen into a lamp, he could slow the evaporation of tungsten from the filament. He then found that thin filaments radiated heat faster than thick filaments, but the same thin filament–wound into a coil–radiated heat as if it were a solid rod the diameter of the coil. By 1913 Langmuir had gas–filled lamps that gave 12 to 20 lumens per watt (lpw), while Coolidge's vacuum lamps gave about 10 lpw.
During the 1910s GE began phasing-in Langmuir's third generation tungsten lamps, calling them "Mazda C" lamps. Although today's lamps are different in detail (for example, argon is used rather than nitrogen), the basic concept is still the same. The lamp seen here was sent to the National Bureau of Standards in the mid 1920s for use as a standard lamp.
Lamp characteristics: Brass medium-screw base with skirt and glass insulator. Two tungsten filaments (both are C9 configuration, mounted in parallel) with 6 support hooks and a support attaching each lead to the stem. The stem assembly includes welded connectors, angled-dumet leads, and a mica heat-shield attached to the leads above the press. The shield clips are welded to the press. Lamp is filled with nitrogen gas. Tipless, G-shaped envelope with neck.
New lighting inventions occasionally appear from unexpected directions. The development of this microwave-powered lamp provides a case in point. In 1990 Fusion Systems was a small company with a successful, highly specialized product, an innovative ultraviolet (UV) industrial lighting system powered by microwaves.
Discharge lamps typically use electrodes to support an electric arc. Tungsten electrodes are most common, so materials that might erode tungsten can't be used in the lamp and care must be taken to not melt the electrodes. Fusion's lamp side-stepped this problem by eliminating electrodes entirely. Microwave energy from an external source energized the lamp. This opened the way for experiments with non-traditional materials, including sulfur.
During the 1980s engineer Michael Ury, physicist Charles Wood, and their colleagues experimented several times with adapting their UV system to produce visible light without success. In 1990, they tried placing sulfur in a spherical bulb instead of a linear tube. Sulfur could give a good quality light, but did not work well in the linear tube. Other elements only gave marginal results in the spherical bulb. But when they tested sulfur in the spherical lamp they found what they hoped for: lots of good visible light with little invisible UV or infrared rays.
They began setting up "crude" lamps like this one (one of the first ten according to Ury) in order to learn more about the new light source. In the mid-1990s Fusion began trying to sell their sulfur bulbs with limited success. The lamp rotated at 20,000 rpm so that the temperature stayed even over the surface, and a fan was needed for cooling. The fan and spin motor made noise and reduced energy efficiency of the total system. Then they found that the bulbs lasted longer than the magnetrons used to generate the microwaves that powered them. Finding inexpensive magnetrons proved too difficult, and the company stopped selling the product in 2002.
Lamp characteristics: A quartz stem with notch near the bottom serves as the base. The notch locks the lamp into its fixture. The sphere has an argon gas filling, and the yellow material is sulfur condensed on the inner lamp wall. The pattern of condensation indicates lamp was burned base-down. Tipless, G-shaped quartz envelope.
As the 1980s progressed, more companies began marketing compact fluorescent lamps (CFLs). This modular unit was made by Janmar Lighting around 1987. The ballast that controls the electrical arc in the lamp is contained in the base adapter. The globe-shaped cover serves both to diffuse light and to make the lamp less unusual looking. Some consumers dislike the non-traditional shapes of many CFLs and refused to purchase them for that reason.
It is not known if the Philips tube assembly is original to this piece or if it's a replacement. However it does demonstrate that the new plug-in bases developed with CFLs became standardized within a few years of the technology's 1981 introduction.
This unit is a modular CFL with three components: a tube assembly, an adapter, and a cover. Lamp characteristics: Tube assembly is a Philips model PL-7/27. A 7-watt twin-tube unit with connecting bridge-weld mounted on a G23 plastic base with aluminum skirt. The adapter has a brass medium-screw base-shell with retainer. The insulator is part of the plastic skirt that houses a magnetic ballast. A G23 socket is on top and male threads to attach the cover. Cover is a G-shaped, white-glass envelope with black plastic collar at bottom, threaded to mount onto adapter. Electrical ratings are 120 volts, 60 hertz, .18 amps.
After the initial introduction of compact fluorescent lamps (CFL) in 1981, many competing lamp companies placed products on the market. The first thirty years of compact fluorescents has seen a wide array of styles and features offered as lamp makers attempt to set their products apart from competitors.
This U-Lite unit is an integral CFL—the lamp is all one piece. Integral lamps are typically more expensive to replace than modular designs that allow the user to replace only the part that fails. However integral units do not require suppliers to stock replacement parts, and they free consumers from having to try to select the correct part for their device.
The U-Lite used a slightly larger tube than other companies' CFLs. That simplified the manufacturing process and reduced stress on the phosphor, though it limited the number of tube-legs that could be put on a single lamp. As many as four pairs have been mounted on CFL designs from other makers. More tubes of the size used on the U-Lite would make the lamp too large to install in many fixtures.
Lamp characteristics: Brass medium-screw base with plastic skirt, glass insulator. A magnetic ballast is housed inside the skirt. Single-bend (T-8) arc-tube with reduced diameter bend and internal phosphor coating. No separate, external envelope.
Miniature metal-halide lamp designed for indoor use. This was GE's competitive response to compact fluorescent lamps introduced by Philips and Westinghouse, and it failed in the market.
Introducing a new product involves more than just crafting an advertising campaign aimed at consumers. A company must also convince potential distributors (both wholesale and retail) to stock the product. That task is made easier if one can visually show the differences between the old product and the new.
This lamp is a Philips "SL Electronic" demonstration piece made about 1985. Philips' original "SL" compact fluorescent lamp came equipped with a magnetic, coil-core ballast when introduced in 1981. The newer version replaced that magnetic ballast with an electronic ballast, raising energy efficiency in the lamp. This demonstration lamp has a clear base-skirt allowing whoever demonstrates the lamp to show the electronic circuitry.
All fluorescent lamps require a ballast due to a quirk engineers call negative-resistance characteristic. The electrical resistance inside a fluorescent lamp is very high when the lamp is off—that's why fluorescent lamps need starters. But once the current is flowing through the lamp the resistance drops, causing the lamp to draw more current, which drops the resistance further, causing still more current to be drawn. Without a control device in the circuit, this cycle would quickly destroy the lamp. A ballast, whether magnetic or elecronic, regulates the amount of current flowing through the lamp and prevents the cycle from occurring.
Lamp characteristics: Brass, medium-screw base with clear plastic skirt that houses an electronic ballast and a starter. Fluorescent tube includes two electrodes, mercury, and a phosphor coating. A corrugated plastic cover protects the tube. Eight slots in the cover allow excess heat to escape. Rating: 18 watts.
When most people think of electric lighting, they think of ordinary lamps used for lighting rooms or shops. But many types of lamps are made for use in highly specialized applications. One example is a successful product made by Fusion Systems. Founded by four scientists and an engineer, the company markets an ultraviolet (UV) lighting system powered by microwaves. Introduced in 1976, the system found a market in industrial processing as a fast, efficient way to cure inks. A major brewery, for example, purchased the system for applying labels to beer cans and quickly curing their inks while the bottles went down the production line. U.S. patents issued for this lighting system include 3872349, 4042850 and 4208587.
The lamp seen here, referred to as a "TEM lamp" is a typical production unit. As in a fluorescent lamp, this lamp makes ultraviolet light by energizing mercury vapor. Fluorescents and other conventional lamps pass an electric current between two electrodes to energize the mercury. But Fusion's lamp has no electrodes. Instead the lamp is placed in a specially made fixture similar in principle to a household microwave oven. The microwaves energize the mercury vapor directly. A small dose of metal halides is also energized in the lamp. The choice of metal halides allows specific wavelengths of light to be produced to meet different needs.
Profits made from the production of this industrial lamp were used by the company to support research and development of a microwave-powered lamp that made visible light. Instead of mercury that lamp used sulfur. However this sulfur lamp did not sell well when introduced in the mid-1990s.
Lamp characteristics: Clear quartz tube containing a metal-halide pellet and a drop of mercury. No electrodes. The air-cooled tube is radiated by microwaves and produces ultraviolet light.
As knowledge of materials and experience making electric lamps grew in the early 20th century, more efficient light sources began to reach the market. In 1932 a collaboration of General Electric Company of England (GEC), Philips in the Netherlands, and Osram in Germany introduced a discharge lamp that used low-pressure sodium vapor. The key to a workable sodium lamp lay in a special glass (called borate glass) that could withstand the very corrosive nature of sodium. Arthur Compton in the U.S. described such a glass in 1926. But it took five more years to learn how to actually produce it so that a lamp could be made.
Discharge lamps make light by passing an electrical current through a gas, in this case sodium vapor. The current energizes the gas which then emits light. In this lamp, the sodium is contained by the bulb, which is lined with the borate glass. The lamp in turn is mounted inside a larger, double-walled glass jacket (part of the light fixture, not shown) to keep the temperature around the lamp stable during operation. Sodium light is a stark yellow suitable only for use in applications like street lighting, but the energy efficiency is very high. Early models gave 40 lumens per watt (lpw), a figure that reached about 100 lpw by 1960. Today's low-pressure sodium lamps give close to 200 lpw, the most energy efficient light source commercially available.
This lamp was made for street-lighting use by (U.S.) General Electric around 1940.
Lamp characteristics: Plastic, four-post base. Re-coiled tungsten electrodes mounted inside metal shields. The small brown cylinder mounted near the stem press is a starting resistance. Six asbestos insulator rings mount on the lamp's neck and are secured by the brass collar. (The rings have been removed and stored while the lamp is on display and are not in this picture.) Tipless, T-shaped envelope with about 70% of the inner wall coated by condensed sodium.