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Photoflash Capacitor
A photoflash capacitor is an electrolytic capacitor used in flash cameras, professional flashes, and also in solid-state laser power supplies. Their usual purpose is to briefly power a high-voltage flash tube, used to illuminate a photographic subject or optically pump a laser rod. As flash tubes require very high current for a very short time to operate, photoflash capacitors are designed to supply high discharge current pulses without excessive internal heating. Fundamentals The principal properties of a capacitor are capacitance, working voltage, equivalent series resistance (ESR), equivalent series inductance (ESL), and working temperature Compared with electrolytic capacitors usually used for power supply filtering at power frequency, a photoflash capacitor is designed to have lower ESR, ESL, and capacitance manufacturing tolerance, but does not need as high a working temperature. Design The light energy emitted by a flash is supplied by the capacitor, and is proportion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolytic Capacitor
An electrolytic capacitor is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the cathode or negative plate of the capacitor. Due to their very thin dielectric oxide layer and enlarged anode surface, electrolytic capacitors have a much higher capacitance-voltage (CV) product per unit volume than ceramic capacitors or film capacitors, and so can have large capacitance values. There are three families of electrolytic capacitor: aluminum electrolytic capacitors, tantalum electrolytic capacitors, and niobium electrolytic capacitors. The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals, and for storing large amounts of energy. They are widely used for decoupling or noise filtering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash (photography)
A flash is a device used in photography that produces a brief burst of light (typically lasting 1/1000 to 1/200 of a second) at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light. ''Flash'' refers either to the flash of light itself or to the electronic flash unit discharging the light. Most current flash units are electronic, having evolved from single-use flashbulbs and flammable powders. Modern cameras often activate flash units automatically. Flash units are commonly built directly into a camera. Some cameras allow separate flash units to be mounted via a standardized accessory mount bracket (a ''hot shoe''). In professional studio equipment, flashes may be large, standalone units, or studio strobes, powered by special battery packs or connected to mains power. They are either synchronized with the camera using a flas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a small hole (the aperture) that allows light to pass through in order to capture an image on a light-sensitive surface (usually a Image sensor, digital sensor or photographic film). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera, and the aperture can be narrowed or widened. A Shutter (photography), shutter mechanism determines the amount of time the photosensitive surface is exposed to the light. The still image camera is the main instrument in the art of photography. Captured images may be reproduced later as part of the process of photography, digital imaging, or photographic printing. Similar artistic fields in the moving-image camera dom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Tube
Flash, flashes, or FLASH may refer to: Arts, entertainment, and media Fictional aliases * Flash (DC Comics character), several DC Comics superheroes with super speed: ** Flash (Barry Allen) ** Flash (Jay Garrick) ** Wally West, the first Kid Flash and third adult Flash ** Bart Allen, the second Kid Flash who also became the adult hero for a time * Flash (G.I. Joe), a character in the G.I. Joe universe * Flash, a robot in the video game Brave series, ''Brave Saga 2'' * Flash, a character in the comedy film ''Daddy Day Care'' (2003) * Flash, a character in the TV science fiction drama ''Real Humans'' * Flash, a character in the 1989 American action comedy movie ''Speed Zone#Cast, Speed Zone'' * Flash, a character in the TV sitcom ''List of Step by Step episodes, Step by Step'' * Flash, a character in the film ''Zootopia'' (2016) * Flash Gordon, the titular hero of science fiction comic strip * My Little Pony: Equestria Girls#Flash Sentry, Flash Sentry, in ''My Little Pony: Friends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalent Series Resistance
Practical capacitors and inductors as used in electric circuits are not ideal components with only capacitance or inductance. However, they can be treated, to a very good degree of approximation, as being ideal capacitors and inductors in series with a resistance; this resistance is defined as the equivalent series resistance (ESR). If not otherwise specified, the ESR is always an AC resistance, which means it is measured at specified frequencies, 100 kHz for switched-mode power supply components, 120 Hz for linear power-supply components, and at its self-resonant frequency for general-application components. Additionally, audio components may report a " Q factor", incorporating ESR among other things, at 1000 Hz. Overview Electrical circuit theory deals with ideal resistors, capacitors and inductors, each assumed to contribute only resistance, capacitance or inductance to the circuit. However, all components have a non-zero value of each of these parameters. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalent Series Inductance
Equivalent series inductance (ESL) is an effective inductance that is used to describe the inductive part of the impedance of certain electrical components. Overview The theoretical treatment of devices such as capacitors and resistors tends to assume they are ''ideal'' or "perfect" devices, contributing only capacitance or resistance to the circuit. However, all physical devices are connected to a circuit through conductive leads and paths, which contain inherent, usually unwanted, inductance. This means that physical components contain some inductance in addition to their other properties.{{Cite book, last=Maniktala, first=Sanjaya, url=https://books.google.com/books?id=zMVTv6py7woC&dq=%22Equivalent+series+inductance%22&pg=PA631, title=Switching Power Supplies A - Z, date=2012-04-18, publisher=Elsevier, isbn=978-0-12-386533-5, pages=631, language=en An easy way to deal with these inherent inductances in circuit analysis is by using a lumped element model to express each physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country. During the development of commercial electric power systems in the late-19th and early-20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240 V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manufacturing Tolerance
Engineering tolerance is the permissible limit or limits of variation in: # a physical dimension; # a measured value or physical property of a material, manufactured object, system, or service; # other measured values (such as temperature, humidity, etc.); # in engineering and safety, a physical distance or space (tolerance), as in a truck (lorry), train or boat under a bridge as well as a train in a tunnel (see structure gauge and loading gauge); # in mechanical engineering, the space between a bolt and a nut or a hole, etc. Dimensions, properties, or conditions may have some variation without significantly affecting functioning of systems, machines, structures, etc. A variation beyond the tolerance (for example, a temperature that is too hot or too cold) is said to be noncompliant, rejected, or exceeding the tolerance. Considerations when setting tolerances A primary concern is to determine how wide the tolerances may be without affecting other factors or the outcome of a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microfarad
The farad (symbol: F) is the unit of electrical capacitance, the ability of a body to store an electrical charge, in the International System of Units (SI). It is named after the English physicist Michael Faraday (1791–1867). In SI base units 1 F = 1 kg−1⋅ m−2⋅ s4⋅ A2. Definition The capacitance of a capacitor is one farad when one coulomb of charge changes the potential between the plates by one volt. Equally, one farad can be described as the capacitance which stores a one-coulomb charge across a potential difference of one volt. The relationship between capacitance, charge, and potential difference is linear. For example, if the potential difference across a capacitor is halved, the quantity of charge stored by that capacitor will also be halved. For most applications, the farad is an impractically large unit of capacitance. Most electrical and electronic applications are covered by the following SI prefixes: *1 mF (millifarad, one thousandth () ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forrest Mims
Forrest M. Mims III is an American amateur scientist,'Country Scientist' starting column today in Express-News ForrestMims.org, October 30, 2006 magazine columnist, and author of ''Getting Started in Electronics'' and ''Engineer's Mini-Notebook'' series of instructional books that were originally sold in electronics stores and are still in print. Mims graduated from in 1966 with a major in government and minors in English and history. He became a commissioned officer in the |
Disc Film
Disc film is a discontinued still-photography film format that was aimed at the consumer market. It was introduced by Kodak in 1982. Technical details The film is in the form of a flat disc, and is fully housed within a plastic cartridge. Each disc holds fifteen 10 × 8 mm exposures, arranged around the outside of the disc, with the disc being rotated 24° between successive images. The system was a consumer-oriented product, and most cameras are self-contained units with no expansion capability. The disc film allows them to be compact and considerably thinner than other cameras. The cameras are very simple to load and unload, and are generally completely automated. The cassette has a built-in dark slide to prevent stray light reaching the film when the disc is removed. As the film is rotated on a disc instead of over a spool, the cassette is very thin. The flat nature of the format also led to the potential advantage of greater sharpness over curved spool-based cassette ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
