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Tin Can Telephone
A tin can phone is a type of acoustic (non-electrical) speech-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut string or wire. It is a particular case of mechanical telephony, where sound (i.e., vibrations in the air) is converted into vibrations along a liquid or solid medium. These vibrations are transmitted through the medium (string) and then converted back to sound. History Before the invention of the electromagnetic telephone, there were mechanical acoustic devices for transmitting spoken words and music over a greater distance, faster than the speed of sound in air. The very earliest mechanical telephones were based on transmission through pipes or other physical media, and among the very earliest experiments were those conducted by the British physicist and polymath Robert Hooke from 1664 to 1685.McVeigh, Daniel PAn Early History of the Telephone: 1664–1866: Robert Hooke's Acoustic Experiments and Ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrographia
''Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses. With Observations and Inquiries Thereupon.'' is a historically significant book by Robert Hooke about his observations through various lenses. It was the first book to include illustrations of insects and plants as seen through microscopes. Published in January 1665, the first major publication of the Royal Society, it became the first scientific best-seller, inspiring a wide public interest in the new science of microscopy. The book originated the biological term ''cell''. Observations Hooke most famously describes a fly's eye and a plant cell (where he coined that term because plant cells, which are walled, reminded him of the cells in a honeycomb"... I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular .these pores, or cells, .were indeed the first microscopical pores I ever saw, and perhaps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound-powered Telephone
A sound-powered telephone is a communication device that allows users to talk to each other with the use of a handset, similar to a conventional telephone, but without the use of external power. This technology has been used since at least 1944 for both routine and emergency communication on ships to allow communication between key locations on a vessel if power is unavailable. A sound-powered phone circuit can have two or more stations on the same circuit. The circuit is always live, thus a user begins speaking rather than dialing another station. Sound-powered telephones are not normally connected to a telephone exchange. Operation The microphone transducer converts sound pressure from a user's voice into an electric current, which is then converted back to sound by a transducer at the receiver nodes. The most significant distinction between ordinary telephones and sound-powered telephones is in the operation of the microphone. Since the microphones used in most teleph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of The Telephone
This history of the telephone chronicles the development of the electrical telephone, and includes a brief overview of its predecessors. The first telephone patent was granted to Alexander Graham Bell in 1876. Mechanical and acoustic devices Before the invention of electromagnetic telephones, mechanical acoustic devices existed for transmitting speech and music over a greater distance. This distance was greater than that of normal direct speech. The earliest mechanical telephones were based on sound transmission through pipes or other physical media. The acoustic tin can telephone, or "lovers' phone", has been known for centuries. It connects two diaphragms with a taut string or wire, which transmits sound by mechanical vibrations from one to the other along the wire (and not by a modulated electric current). The classic example is the children's toy made by connecting the bottoms of two paper cups, metal cans, or plastic bottles with tautly held string. Some of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tension (physics)
In physics, tension is described as the pulling force transmitted axially by the means of a string, a rope, chain, or similar object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression (physics), compression. At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length. Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newton (unit), newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, such as the movement of a tire on a gravel road. Vibration can be desirable: for example, the motion of a tuning fork, the reed in a woodwind instrument or harmonica, a mobile phone, or the cone of a loudspeaker. In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For example, the vibrational motions of engines, electric motors, or any mechanical device in operation are typically unwanted. Such vibrations could be caused by imbalances in the rotating parts, uneven friction, or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations. The studies of sound and vibration are closely related. Sound, or pressure waves, are generated by vibrating structures (e.g. vocal cords); thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Wave
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Acoustics Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an ''acoustician'', while someone working in the field of acoustical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphragm (mechanical Device)
In mechanical engineering, mechanics, a diaphragm is a sheet of a semi-flexible material anchored at its periphery and most often round in shape. It serves either as a barrier between two chambers, moving slightly up into one chamber or down into the other depending on differences in pressure, or as a device that vibrates when certain frequencies are applied to it. A diaphragm pump uses a diaphragm to pump a fluid. A typical design is to have air on one side constantly vary in pressure, with fluid on the other side. The increase and decrease in volume caused by the action of the diaphragm alternately forces fluid out the chamber and draws more fluid in from its source. The action of the diaphragm is very similar to the action of a plunger with the exception that a diaphragm responds to changes in pressure rather than the mechanical force of the shaft. A diaphragm pressure tank is a tank which has pressurant sealed inside on one side of the diaphragm. It is favored in certain appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Graham Bell
Alexander Graham Bell (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and Telegraph Company (AT&T) in 1885. Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf; profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone, on March 7, 1876. Bell considered his invention an intrusion on his real work as a scientist and refused to have a telephone in his study. Many other inventions marked Bell's later life, including groundbreaking work in optical telecommunications, hydrofoils, and aeronautics. Bell also had a strong influence on the National Geographic Society and its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niche Market
A niche market is the subset of the market on which a specific product is focused. The market niche defines the product features aimed at satisfying specific market needs, as well as the price range, production quality and the demographics that it is intended to target. It is also a small market segment. Sometimes, a product or service can be entirely designed to satisfy a niche market. Not every product can be defined by its market niche. The niche market is highly specialized, and aiming to survive among the competition from numerous super companies. Even established companies create products for different niches; Hewlett-Packard has all-in-one machines for printing, scanning and faxing targeted for the home office niche, while at the same time having separate machines with one of these functions for big businesses. While you may have explicit moving items effectively at the top of the priority list. Although you can build your chances of achievement by beginning with a niche mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal (electronics)
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' includes audio, video, speech, image, sonar, and radar as examples of signal. A signal may also be defined as observable change in a quantity over space or time (a time series), even if it does not carry information. In nature, signals can be actions done by an organism to alert other organisms, ranging from the release of plant chemicals to warn nearby plants of a predator, to sounds or motions made by animals to alert other animals of food. Signaling occurs in all organisms even at cellular levels, with cell signaling. Signaling theory, in evolutionary biology, proposes that a substantial driver for evolution is the ability of animals to communicate with each other by developing ways of signaling. In human engineering, signals are typi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consolidated Telephone Co
Consolidated may refer to: *Consolidated (band) **''¡Consolidated!'', a 1989 extended play *Consolidated Aircraft (later Convair), an aircraft manufacturer * Consolidated city-county *Consolidated Communications * Consolidated school district *Consolidated Foods The Sara Lee Corporation was an American consumer-goods company based in Downers Grove, Illinois. It had operations in more than 40 countries and sold its products in over 180 countries. Its international operations were headquartered in Utrecht ... See also * * Consolidation (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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