|
Marconi Instruments
Marconi Instruments Limited (MI) was a British company, one of the Marconi group of companies, formerly part of GEC. Originally formed in 1936, there was a buyout of Marconi-Ekco Instruments to form the company Marconi Instruments in 1941. The company was based in St Albans, Colchester and Stevenage (where it eventually consolidated), all in southern England. Prior to the consolidation in Stevenage, its main site was at Longacres on the eastern outskirts of St Albans, where it was the largest employer. There were four other sites, one at Hedley Road, one on Hatfield Road, St Albans ( Fleetville Works), one on the Donibristle Industrial Estate in Fife, Scotland and one at Luton Airport, Luton. The company produced electronic test and measurement equipment and systems, including automatic test equipment. It was known for its extensive range of signal generators, from audio up to microwave frequencies. It also made oscilloscopes, voltmeters, spectrum analysers, frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GEC Marconi Logo
GEC or Gec may refer to: Education * Gedo Education Committee, in Somalia * Glen Eira College, in Caulfield East, Victoria, Australia * Goa Engineering College, India * Government Engineering College (other) * Guild for Exceptional Children, in New York City, US * Gwalior Engineering College, India Other uses * Aleksandar Gec (1928–2008), Serbian basketball player * General Electric Company, a former British engineering conglomerate * General entertainment channel, a type of TV or radio channel * Global Environment Centre, Malaysia * Golden Empire Council, of the Boy Scouts of America * '' Gran Enciclopèdia Catalana'', a Catalan-language encyclopedia * Greater Egyptian Conference, an athletics conference in Illinois, US * Green Electronics Council, US * Grêmio Esportivo Catanduvense, a former Brazilian football club * Grounding electrode conductor * Lufthansa Cargo Lufthansa Cargo AG is a German cargo airline and a wholly owned subsidiary of Lufthansa. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the north and west, the North Sea to the northeast and east, and the Irish Sea to the south. It also contains more than 790 islands, principally in the archipelagos of the Hebrides and the Northern Isles. Most of the population, including the capital Edinburgh, is concentrated in the Central Belt—the plain between the Scottish Highlands and the Southern Uplands—in the Scottish Lowlands. Scotland is divided into 32 administrative subdivisions or local authorities, known as council areas. Glasgow City is the largest council area in terms of population, with Highland being the largest in terms of area. Limited self-governing power, covering matters such as education, social services and roads and transportation, is devolved from the Scott ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Counter
A frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency counters usually measure the number of cycles of oscillation, or pulses per second in a periodic electronic signal. Such an instrument is sometimes referred to as a cymometer, particularly one of Chinese manufacture. Operating principle Most frequency counters work by using a counter which accumulates the number of events occurring within a specific period of time. After a preset period known as the ''gate time'' (1 second, for example), the value in the counter is transferred to a display and the counter is reset to zero. If the event being measured repeats itself with sufficient stability and the frequency is considerably lower than that of the clock oscillator being used, the resolution of the measurement can be greatly improved by measuring the time required for an entire number of cycles, rather than counting the number of entire cycles observed for a pre-set ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrum Analyser
A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. The input signal that most common spectrum analyzers measure is electrical; however, spectral compositions of other signals, such as acoustic pressure waves and optical light waves, can be considered through the use of an appropriate transducer. Spectrum analyzers for other types of signals also exist, such as optical spectrum analyzers which use direct optical techniques such as a monochromator to make measurements. By analyzing the spectra of electrical signals, dominant frequency, power, distortion, harmonics, bandwidth, and other spectral components of a signal can be observed that are not easily detectable in time domain waveforms. These parameters are useful in the characterization of electronic devices, such as wireless transmitters. The display of a spectru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltmeter
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage measured and can be built from a galvanometer and series resistor. Meters using amplifiers can measure tiny voltages of microvolts or less. Digital voltmeters give a numerical display of voltage by use of an analog-to-digital converter. Voltmeters are made in a wide range of styles, some separately powered (e.g. by battery), and others powered by the measured voltage source itself. Instruments permanently mounted in a panel are used to monitor generators or other fixed apparatus. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter, are standard test instruments used in electrical and electronics work. Any measurem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscilloscope
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetitive or single waveforms on the screen that would otherwise occur too briefly to be perceived by the human eye. The displayed waveform can then be analyzed for properties such as amplitude, frequency, rise time, time interval, distortion, and others. Originally, calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument. Modern digital instruments may calculate and display these properties directly. Oscilloscopes are used in the sciences, medicine, engineering, automotive and the telecommunications industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used to analyze an automotive ign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF (millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Frequency
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. The generally accepted standard hearing range for humans is 20 to 20,000 Hz. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. High frequencies are the first to be affected by hearing loss due to age or prolonged exposure to very loud noises. Sound frequencies above 20 kHz are called ultrasonic. Frequencies and descriptions See also *Absolute threshold of hearing *Hypersonic effect, controversial claim for human perception above 20,000 Hz *Loudspeaker *Musical acoustics *Piano key frequencies *Scientific pitch notation *Whistle register The whistle register (also called the flute regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Generator
A signal generator is one of a class of electronic devices that generates electrical signals with set properties of amplitude, frequency, and wave shape. These generated signals are used as a stimulus for electronic measurements, typically used in designing, testing, troubleshooting, and repairing electronic or electroacoustic devices, though it often has artistic uses as well. There are many different types of signal generators with different purposes and applications and at varying levels of expense. These types include function generators, RF and microwave signal generators, pitch generators, arbitrary waveform generators, digital pattern generators, and frequency generators. In general, no device is suitable for all possible applications. A signal generator may be as simple as an oscillator with calibrated frequency and amplitude. More general-purpose signal generators allow control of all the characteristics of a signal. Modern general-purpose signal generators will have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yahoo Groups
Yahoo! Groups was a free-to-use system of electronic mailing lists offered by Yahoo!. Prior to February 2020, Yahoo! Groups was one of the world's largest collections of online discussion boards. It allowed members to subscribe to various groups, read subscribed discussions online, view and share photos, files and bookmarks within a group, access a group calendar, create polls for group members, and receive email notifications of new discussion topics. Some groups were simply announcement boards, to which only the group moderators could post, while others were discussion forums. Depending on each group's settings, membership could be open to everyone or only to invited and/or approved people. On February 1, 2020, Yahoo! removed online access to discussions and all other features except simple membership management, essentially turning all groups into mailing lists, and on October 13, 2020, it announced that Yahoo Groups would shut down completely on December 15, 2020. History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yahoo
Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo! Inc. (2017–present), Yahoo Inc., which is 90% owned by investment funds managed by Apollo Global Management and 10% by Verizon Communications. It provides a web portal, search engine Yahoo! Search, Yahoo Search, and related services, including My Yahoo!, Yahoo! Mail, Yahoo Mail, Yahoo! News, Yahoo News, Yahoo! Finance, Yahoo Finance, Yahoo! Sports, Yahoo Sports and its advertising platform, Yahoo! Native. Yahoo was established by Jerry Yang and David Filo in January 1994 and was one of the pioneers of the early Internet era in the 1990s. However, usage declined in the late 2000s as some services discontinued and it lost market share to Facebook and Google. History Founding In January 1994, Yang and Filo were electrical engineering graduate students at Stanford University, when they created a website named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EBay
eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became a notable success story of the dot-com bubble. eBay is a multibillion-dollar business with operations in about 32 countries, as of 2019. The company manages the eBay website, an online auction and shopping website in which people and businesses buy and sell a wide variety of goods and services worldwide. The website is free to use for buyers, but sellers are charged fees for listing items after a limited number of free listings, and an additional or separate fee when those items are sold. In addition to eBay's original auction-style sales, the website has evolved and expanded to include: instant "Buy It Now" shopping; shopping by Universal Product Code, ISBN, or other kind of SKU number (via Half.com, which was shut down in 2017); and othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.png "Click for more on -> Yahoo Groups")
