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Buzzer
A buzzer or beeper is an audio signaling device, which may be mechanical, electromechanical, or piezoelectric (''piezo'' for short). Typical uses of buzzers and beepers include alarm devices, timers, train and confirmation of user input such as a mouse click or keystroke. History Electromechanical The electric buzzer was invented in 1831 by Joseph Henry. They were mainly used in early doorbells until they were phased out in the early 1930s in favor of musical chimes, which had a softer tone. Piezoelectric Piezoelectric buzzers, or piezo buzzers, as they are sometimes called, were invented by Japanese manufacturers and fitted into a wide array of products during the 1970s to 1980s. This advancement mainly came about because of cooperative efforts by Japanese manufacturing companies. In 1951, they established the Barium Titanate Application Research Committee, which allowed the companies to be "competitively cooperative" and bring about several piezoelectric innovations an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buzzer Interior
A buzzer or beeper is an audio signaling device, which may be mechanical, electromechanical, or piezoelectric (''piezo'' for short). Typical uses of buzzers and beepers include alarm devices, timers, train and confirmation of user input such as a mouse click or keystroke. History Electromechanical The electric buzzer was invented in 1831 by Joseph Henry. They were mainly used in early doorbells until they were phased out in the early 1930s in favor of musical chimes, which had a softer tone. Piezoelectric Piezoelectric buzzers, or piezo buzzers, as they are sometimes called, were invented by Japanese manufacturers and fitted into a wide array of products during the 1970s to 1980s. This advancement mainly came about because of cooperative efforts by Japanese manufacturing companies. In 1951, they established the Barium Titanate Application Research Committee, which allowed the companies to be "competitively cooperative" and bring about several piezoelectric innovations and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Bell
An electric bell is a mechanical or electronic bell that functions by means of an electromagnet. When an electric current is applied, it produces a repetitive buzzing, clanging or ringing sound. Electromechanical bells have been widely used at railroad crossings, in telephones, fire and burglar alarms, as school bells, doorbells, and alarms in industrial plants, since the late 1800s, but they are now being widely replaced with electronic sounders. An electric bell consists of one or more electromagnets, made of a coil of insulated wire around an iron bar, which attract an iron strip armature with a clapper. Types Interrupter bells How they work The most widely used form is the interrupter bell, which is a mechanical bell that produces a continuous sound when current is applied. See animation, above. The bell or gong ''(B)'', which is often in the shape of a cup or half-sphere, is struck by a spring-loaded arm ''(A)'' with a metal ball on the end called a clapper, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectricity
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electrical field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectric
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electrical field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alarms
An alarm device is a mechanism that gives an audible, visual or other kind of alarm signal to alert someone to a problem or condition that requires urgent attention. Alphabetical musical instruments Etymology The word ''alarm'' comes from the Old French ''a l'arme'' meaning "to the arms", or "to the weapons", telling armed men to pick up their weapons and get ready for action because an enemy may have suddenly appeared. The word ''alarum'' is an archaic form of ''alarm''. It was sometimes used as a call to arms in the stage directions of Elizabethan dramas. The term comes from the Italian ''all'armi'' and appears 89 times in Shakespeare's first folio. Often explained as the off-stage sounds of conflict or disturbance, recent research suggests a bell or drum may have been used to rouse soldiers from sleep. History and development Early alarm devices were often bells, drums, other musical instruments, or any items which made unusual loud noises that attracted the attention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alarm Devices
An alarm device is a mechanism that gives an audible, visual or other kind of alarm signal to alert someone to a problem or condition that requires urgent attention. Alphabetical musical instruments Etymology The word ''alarm'' comes from the Old French ''a l'arme'' meaning "to the arms", or "to the weapons", telling armed men to pick up their weapons and get ready for action because an enemy may have suddenly appeared. The word ''alarum'' is an archaic form of ''alarm''. It was sometimes used as a call to arms in the stage directions of Elizabethan dramas. The term comes from the Italian ''all'armi'' and appears 89 times in Shakespeare's first folio. Often explained as the off-stage sounds of conflict or disturbance, recent research suggests a bell or drum may have been used to rouse soldiers from sleep. History and development Early alarm devices were often bells, drums, other musical instruments, or any items which made unusual loud noises that attracted the attention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timer
A timer is a specialized type of clock used for measuring specific time intervals. Timers can be categorized into two main types. The word "timer" is usually reserved for devices that counts down from a specified time interval, while devices that do the opposite, measuring elapsed time by counting upwards from zero, are called stopwatches. A simple example of the first type is an hourglass. Working method timers have two main groups: hardware and software timers. Most timers give an indication that the time interval that had been set has expired. Time switches, timing mechanisms that activate a switch, are sometimes also called "timers". Hardware Mechanical Mechanical use clockwork to measure time. Manual timers are typically set by turning a dial to the time interval desired; turning the dial stores energy in a mainspring to run the mechanism. They function similarly to a mechanical alarm clock; the energy in the mainspring causes a balance wheel to rotate back and fort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helmholtz Resonance
Helmholtz resonance or wind throb is the phenomenon of air resonance in a cavity, such as when one blows across the top of an empty bottle. The name comes from a device created in the 1850s by Hermann von Helmholtz, the ''Helmholtz resonator'', which he used to identify the various frequencies or musical pitches present in music and other complex sounds.Helmholtz, Hermann von (1885), ''On the sensations of tone as a physiological basis for the theory of music'' Second English Edition, translated by Alexander J. Ellis. London: Longma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doorbell
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security. History William Murdoch, a Scottish inventor, installed a number of his own innovations in his house, built in Birmingham in 1817; one of these was a loud doorbell, that worked using a piped system of compressed air. A precursor to the electric doorbell, specifically a bell that could be rung at a distance via an electric wire, was invented by Joseph Henry around 1831. By the early 1900s, electric doorbells had become commonplace. Wired doorbells In most wired systems, a button on the outside next to the door, locate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock-out Device
A lock-out device is a system used on game shows, particularly trivia shows, to determine in real time which contestant has activated their signal first. The system is designed to detect the first signal it receives and ignore subsequent signals. The system provides some indication of which contestant has signaled, such as a light or sound for each contestant, allowing the relevant parties to clearly determine who has signaled first. Perhaps the most famous modern game show to use a lock-out device is ''Jeopardy! ''Jeopardy!'' is an American game show created by Merv Griffin. The show is a quiz competition that reverses the traditional question-and-answer format of many quiz shows. Rather than being given questions, contestants are instead given genera ...'', which uses a sophisticated system that is so fundamental to the game, mastering the signaling device is commonly said to be at least as important as knowing the correct response to each clue. Once the host has finished ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annunciator Panel
An annunciator panel, also known in some aircraft as the Centralized Warning Panel (CWP) or Caution Advisory Panel (CAP), is a group of lights used as a central indicator of status of equipment or systems in an aircraft, industrial process, building or other installation. Usually, the annunciator panel includes a main warning lamp or audible signal to draw the attention of operating personnel to the annunciator panel for abnormal events or condition. Aviation In the aircraft industry, annunciator panels are groupings of annunciator lights that indicate status of the aircraft's subsystems. The lights are usually accompanied with a test switch, which when pressed illuminates all the lights to confirm they are in working order. More advanced modern aircraft replaces these with the integrated electronic Engine Indicating and Crew Alerting System or Electronic Centralised Aircraft Monitor. An aviation annunciator panel will have a test switch to check for burned out lamps. Indicator l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
