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Carbon Microphone
The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by granules of carbon. One plate is very thin and faces toward the speaking person, acting as a diaphragm (acoustics), diaphragm. Sound waves striking the diaphragm cause it to vibrate, exerting a varying pressure on the granules, which in turn changes the electrical resistance between the plates. Higher pressure lowers the resistance as the granules are pushed closer together. A steady direct current is passed between the plates through the granules. The varying resistance results in a modulation of the current, creating a varying electric current that reproduces the varying pressure of the sound wave. In analogue telephony, this undulating current is directly passed through the telephone wires to a telephone exchange, and is routed to a reci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Button Microphone
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, carbon-12, C and carbon-13, C being stable, while carbon-14, C is a radionuclide, decaying with a half-life of 5,700 years. Carbon is one of the timeline of chemical element discoveries#Pre-modern and early modern discoveries, few elements known since antiquity. Carbon is the 15th abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the abundance of the chemical elements, fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual abi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Amplifier
An audio power amplifier (or power amp) electronic amplifier, amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup (music technology), pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address, home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback signal chain, chain before the signal is sent to the loudspeakers. The preceding stages in such a chain are low-power audio amplifiers which perform tasks like preamplifier, pre-amplification of the signal, equalization (audio), equalization, mixing console, mixing different input signals. The inputs can also be any number of audio sources like record players, CD players, digital audio players and cassette players. Most audio power amplifiers require these low- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is defined as a circuit that has a power gain greater than one. An amplifier can be either a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Microphone
The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by granules of carbon. One plate is very thin and faces toward the speaking person, acting as a diaphragm (acoustics), diaphragm. Sound waves striking the diaphragm cause it to vibrate, exerting a varying pressure on the granules, which in turn changes the electrical resistance between the plates. Higher pressure lowers the resistance as the granules are pushed closer together. A steady direct current is passed between the plates through the granules. The varying resistance results in a modulation of the current, creating a varying electric current that reproduces the varying pressure of the sound wave. In analogue telephony, this undulating current is directly passed through the telephone wires to a telephone exchange, and is routed to a reci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by Charles II of England, King Charles II and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the society's president, according to a set of statutes and standing orders. The members of Council and the president are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Wave
Acoustic waves are types of waves that propagate through matter—such as gas, liquid, and/or solids—by causing the particles of the medium to compress and expand. These waves carry energy and are characterized by properties like acoustic pressure, particle velocity, and acoustic intensity. The speed of an acoustic wave depends on the properties of the medium it travels through; for example, it travels at approximately 343 meters per second in air, and 1480 meters per second in water. Acoustic waves encompass a broad range of phenomena, from audible sound to seismic waves and ultrasound, finding applications in diverse fields like acoustics, engineering, and medicine. Wave properties An acoustic wave is a mechanical wave that transmits energy through the movements of atoms and molecules. Acoustic waves transmit through fluids in a longitudinal manner (movement of particles are parallel to the direction of propagation of the wave); in contrast to electromagnetic waves that tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Edison
Thomas Alva Edison (February11, 1847October18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventions, which include the phonograph, the motion picture camera, and early versions of the electric Incandescent light bulb, light bulb, have had a widespread impact on the modern industrial society, industrialized world. He was one of the first inventors to apply the principles of organized science and teamwork to the process of invention, working with many researchers and employees. He established the first industrial research laboratory. Edison was raised in the American Midwest. Early in his career he worked as a telegraph operator, which inspired some of his earliest inventions. In 1876, he established his first laboratory facility in Menlo Park, New Jersey, where many of his early inventions were developed. He later established a botanical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emile Berliner
Emile Berliner (May 20, 1851 – August 3, 1929) originally Emil Berliner, was a German-American inventor. He is best known for inventing the lateral-cut flat disc gramophone record, record (called a "gramophone record" in British and American English) used with a gramophone. He founded the Berliner Gramophone, United States Gramophone Company in 1894;Library of Congress"Emile Berliner and the Birth of the Recording Industry: The Gramophone" Retrieved 2017-01-19. The Gramophone Company in London, England, in 1897; Deutsche Grammophon in Hanover, Germany, in 1898; and Berliner Gramophone#Berliner Gram-o-phone Company of Canada, Berliner Gram-o-phone Company of Canada in Montreal in 1899 (chartered in 1904). Berliner also invented what was probably the first radial aircraft engine (1908), a helicopter (1919), and acoustical tiles (1920s). Early life Berliner was born in Hanover, Germany, in 1851 into a Jewish merchant family. He completed an apprenticeship to become a merchant, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Edward Hughes
David Edward Hughes (16 May 1830 – 22 January 1900), was a British-American inventor, practical experimenter, and professor of music known for his work on the printing telegraph and the microphone. He is generally considered to have been born in London but his family moved around that time so he may have been born in Corwen, Wales. His family moved to the U.S. while he was a child and he became a professor of music in Kentucky. In 1855 he patented a printing telegraph. He moved back to London in 1857 and further pursued experimentation and invention, coming up with an improved carbon microphone in 1878. In 1879 he identified what seemed to be a new phenomenon during his experiments: electric sparks generated in one device could be heard in a separate portable microphone apparatus he had set up. It was most probably radio transmissions but this was nine years before electromagnetic radiation was a proven concept and Hughes was convinced by others that his discovery wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency, emergency communications. The term ''"radio amateur"'' is used to specify ''"a duly authorized person interested in radioelectric practice with a purely personal aim and without wikt:pecuniary, pecuniary interest"'' (either direct monetary or other similar reward); and to differentiate it from commercial broadcasting, public safety (police and fire), or two-way radio professional services (maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and ''amateur-satellite service'') is established by the International Telecommunication Union (ITU) through their recommended radio regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AM Broadcasting
AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands. The earliest experimental AM transmissions began in the early 1900s. However, widespread AM broadcasting was not established until the 1920s, following the development of vacuum tube receivers and transmitters. AM radio remained the dominant method of broadcasting for the next 30 years, a period called the " Golden Age of Radio", until television broadcasting became widespread in the 1950s and received much of the programming previously carried by radio. Later, AM radio's audiences declined greatly due to competition from FM (frequency modulation) radio, Digital Audio Broadcasting (DAB), satellite radio, HD (digital) radio, Internet radio, music streaming services, and podca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plain Old Telephone Service
Plain old telephone service (POTS), or publicly offered telephone service, is basic Voice band, voice-grade telephone service. Historically, POTS has been delivered by Analog signal, analog signal transmission over copper loops, but the term also describes Backward compatibility, backward-compatible analog connections offered by digital telephone systems. Copper loop POTS was the standard service offering from telephone companies in the United States from 1876 until 1988, when the Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) was introduced, followed by the development of mobile phone, cellular telephone systems and voice over internet protocol (VoIP). Despite the advent of these technologies, copper loop POTS remains a basic form of residential and small business connection to the telephone network in many parts of the world. The term encapsulates a technology that has been available since the introduction of the public telephone system in the late 19th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
