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Eco-Drive
Eco-Drive is a model range of watches manufactured and marketed worldwide by Citizen Watch Co., Ltd., powered primarily by light. As of 2007, the company estimated the drive system had eliminated the disposal of ten million batteries in North America. Citizen introduced the Eco-Drive line to Asia, Latin America, and Europe in 1995 and to the United States in April, 1996. The Eco-Drive concept introduced several technical refinements over previous solar powered watches, including light-capturing cells that could be made virtually invisible behind the dial instead of highly conspicuous, enhancing the appearance of the watch. History Eco-Drive concept The technical platform that made the Eco-Drive concept possible was the Eco-Drive caliber 7878 movement. This movement was the first light-powered movement where the solar cells could be mounted under the dial. Previous light powered watches from Citizen and other manufacturers had the solar cell(s) mounted directly on the dial. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citizen Holdings
is an electronics company primarily known for its watches and is the core company of a Japanese global corporate group based in Nishitokyo, Tokyo, Japan. In addition to Citizen brand watches, it is the parent of American watch company Bulova, and is also known for manufacturing small electronics such as calculators. History The company was founded in 1930 by Japanese and Swiss investors. It took over Shokosha Watch Research Institute (founded in 1918) and some facilities of the assembly plant opened in Yokohama in 1912 by the Swiss watchmaker Rodolphe Schmid. The brand Citizen was first registered in Switzerland by Schmid in 1918 for watches he sold in Japan. The development of this brand was supported in the 1920s by Count Gotō Shinpei with his hope that watches could become affordable to the general public. The growth of Citizen until World War II relied on technology transfer from Switzerland. Products Atomic timekeeping Citizen launched the world's first multi-band a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz Clock
Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least an order of magnitude more accurate than mechanical clocks. Generally, some form of digital logic counts the cycles of this signal and provides a numerical time display, usually in units of hours, minutes, and seconds. Since the 1980s, when the advent of solid-state digital electronics allowed them to be made compact and inexpensive, quartz timekeepers have become the world's most widely used timekeeping technology, used in most clocks and watches as well as computers and other appliances that keep time. Explanation Chemically, quartz is a specific form of a compound called silicon dioxide. Many materials can be formed into plates that will resonate. However, quartz is also a piezoelectric material: that is, when a quartz crystal is su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Watch
A diving watch, also commonly referred to as a diver's or dive watch, is a watch designed for underwater diving that features, as a minimum, a water resistance greater than , the equivalent of . The typical diver's watch will have a water resistance of around , though modern technology allows the creation of diving watches that can go much deeper. A true contemporary diver's watch is in accordance with the ISO 6425 standard, which defines test standards and features for watches suitable for diving with underwater breathing apparatus in depths of or more. Watches conforming to ISO 6425 are marked with the word DIVER'S to distinguish ISO 6425 conformant diving watches from watches that might not be suitable for actual scuba diving. To a large extent the diver's watch has been superseded by the personal dive computer, which provides an automatically initiated dive timer function along with real-time decompression computation and optionally other functions. History The history of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronograph
A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has an independent sweep second hand and a minute sub-dial; it can be started, stopped, and returned to zero by successive pressure on the stem. More complex chronographs use additional Complication (horology), complications and can have multiple sub-dials to measure seconds, minutes, hours and even fractions of a second. In addition, many modern chronographs use moveable bezels as Tachymeter (watch), tachymeters for rapid calculations of speed or distance. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs were also used heavily in artillery fire in the mid to late 1800s. More modern uses of chronographs involve aircraft piloting, auto racing, Underwater diving, diving and submarine maneuvering. Since the 1980s, the term ''chronograph'' has also been applied to all Watch#Digital, digital watches that incorpor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Quartz
Automatic quartz is a collective term describing watch movements that combine a self-winding rotor mechanism (as used in automatic mechanical watches) to generate electricity with a piezoelectric quartz crystal as its timing element. Such movements aim to provide the advantages of quartz without the inconvenience and environmental impact of batteries. Several manufacturers employ this technique. Mode of operation A rotating pendulum inside the case is attached to a relatively large gear which meshes with a very small pinion. As the wearer moves, the pendulum turns and spins the pinion at a very high speed - up to 100,000 rpm. This is coupled to a miniature electrical generator which charges a storage device which is a capacitor(s) or a rechargeable battery. A typical full charge will last between two weeks and six months. Applications Seiko Japanese company Seiko pioneered the technique which it unveiled at the Baselworld 1986 trade show under the trial name AGM. The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Clock
A radio clock or radio-controlled clock (RCC), and often (incorrectly) referred to as an atomic clock is a type of quartz clock or watch that is automatically synchronized to a time code transmitted by a radio transmitter connected to a time standard such as an atomic clock. Such a clock may be synchronized to the time sent by a single transmitter, such as many national or regional time transmitters, or may use the multiple transmitters used by satellite navigation systems such as Global Positioning System. Such systems may be used to automatically set clocks or for any purpose where accurate time is needed. RC clocks may include any feature available for a clock, such as alarm function, display of ambient temperature and humidity, broadcast radio reception, etc. One common style of radio-controlled clock uses time signals transmitted by dedicated terrestrial longwave radio transmitters, which emit a time code that can be demodulated and displayed by the radio controlled clock. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watch
A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain. Watches were developed in the 17th century from spring-powered clocks, which appeared as early as the 14th century. During most of its history the watch was a mechanical device, driven by clockwork, powered by winding a mainspring, and keeping time with an oscillating balance wheel. These are called ''mechanical watches''. In the 1960s the electronic ''quartz watch'' was invented, which was powered by a battery and kept time with a vibrating quartz crystal. By the 1980s the quartz watch had taken over most of the market from the mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Powered Watch
A solar-powered watch or light-powered watch is a watch that is powered entirely or partly by a solar cell. History A model produced from 1978 by the Riehl Time Corporation was simply described as running on solar power, but having "silicon power cells" that "absorb energy from natural sunlight, daylight, or an ordinary light bulb". Some of the early solar watches of the 1970s had innovative and unique designs to accommodate the array of photovoltaic solar cells needed to power them (Synchronar, Nepro, Sicura and some models by Cristalonic, Alba, Rhythm, Seiko and Citizen). In 1996, Citizen started to sell analog light-powered watches under the Eco-Drive name. Since their introduction, photovoltaic devices have greatly improved their efficiency and thereby their capacity. Watchmakers have developed their technology such that solar-powered watches had by 2009 become a major part of their range. Several other watch manufacturers also use solar technology, such as Orient. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Resistant Mark
Water Resistant is a common mark stamped on the back of wrist watches to indicate how well a watch is sealed against the ingress of water. It is usually accompanied by an indication of the static test pressure that a sample of newly manufactured watches were exposed to in a leakage test. The test pressure can be indicated either directly in units of pressure such as bar, atmospheres, or (more commonly) as an equivalent water depth in metres (in the United States sometimes also in feet). An indication of the test pressure in terms of water depth does not mean a water-resistant watch was designed for repeated long-term use in such water depths. For example, a watch marked 30 metres water resistant cannot be expected to withstand activity for longer time periods in a swimming pool, let alone continue to function at 30 metres under water. This is because the test is conducted only once using static pressure on a sample of newly manufactured watches. As only a small sample is tested ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoelectricity
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when a voltage is applied to it, heat is transferred from one side to the other, creating a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side. This effect can be used to generate electricity, measure temperature or change the temperature of objects. Because the direction of heating and cooling is affected by the applied voltage, thermoelectric devices can be used as temperature controllers. The term "thermoelectric effect" encompasses three separately identified effects: the Seebeck effect, Peltier effect, and Thomson effect. The Seebeck and Peltier effects are different manifestations of the same physical process; textbooks may r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock Face
A clock face is the part of an analog clock (or watch) that displays time through the use of a flat dial with reference marks, and revolving pointers turning on concentric shafts at the center, called hands. In its most basic, globally recognized form, the periphery of the dial is numbered 1 through 12 indicating the hours in a 12-hour cycle, and a short hour hand makes two revolutions in a day. A long minute hand makes one revolution every hour. The face may also include a ''second hand'', which makes one revolution per minute. The term is less commonly used for the time display on digital clocks and watches. A second type of clock face is the 24-hour analog dial, widely used in military and other organizations that use 24-hour time. This is similar to the 12-hour dial above, except it has hours numbered 1–24 around the outside, and the hour hand makes only one revolution per day. Some special-purpose clocks, such as timers and sporting event clocks, are designed for mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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