Editing Buzzer

{{Short description|Audio signalling device}}
{{Other uses}}
A '''buzzer''' or '''beeper''' is an [[Sound|audio]] signaling device,<ref>{{cite web|url=http://www.thefreedictionary.com/buzzer |title=buzzer - definition of buzzer by The Free Dictionary |access-date=22 May 2015}}</ref> which may be [[Machine|mechanical]], [[Electromechanics|electromechanical]], or [[Piezoelectricity|piezoelectric]] (''piezo'' for short). Typical uses of buzzers and beepers include [[alarm devices]], [[timer]]s, [[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 [[doorbell]]s until they were phased out in the early 1930s in favor of musical chimes, which had a softer tone.<ref>{{Cite web|title = The History of the Doorbell by 1800doorbell.com|url = http://www.1800doorbell.com/who-invented-the-doorbell-history.htm|website = www.1800doorbell.com|access-date = 2015-07-12}}</ref>

=== Piezoelectric ===
{{main|Piezoelectric speaker}}
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 inventions.<ref>{{Cite web|title = Piezo Systems: History of Piezoelectricity|url = http://www.piezo.com/tech4history.html|website = www.piezo.com|access-date = 2015-07-12|archive-url = https://web.archive.org/web/20131011004641/http://www.piezo.com/tech4history.html|archive-date = 2013-10-11|url-status = dead}}</ref>

== Types ==

===Electromechanical===
Early devices were based on an electromechanical system identical to an [[electric bell]] without the metal gong. Similarly, a [[relay]] may be connected to interrupt its own actuating [[Electric current|current]], causing the [[Switch|contact]]s to buzz (the contacts buzz at [[Utility frequency|line frequency]] if powered by [[alternating current]]) Often these units were anchored to a wall or ceiling to use it as a sounding board. The word "buzzer" comes from the rasping noise that electromechanical buzzers made.

===Mechanical===
A [[joy buzzer]] is an example of a purely mechanical buzzer and they require drivers. Other examples of them are doorbells.

===Piezoelectric===
[[File:2007-07-24 Piezoelectric buzzer.jpg|thumb|Piezoelectric disk beeper]]
A [[piezoelectric]] element may be driven by an [[Oscillation|oscillating]] electronic circuit or other [[audio signal]] source, driven with a [[piezoelectric audio amplifier]]. Sounds commonly used to indicate that a button has been pressed are a click, a ring or a beep.

[[File:Buzzer interior.JPG|thumb|Interior of a readymade loudspeaker,  showing a piezoelectric-disk-beeper (With 3 electrodes ... including 1 feedback-electrode ( the central, small electrode joined with red wire in this photo), and an oscillator to self-drive the buzzer.]]

A piezoelectric buzzer/beeper also depends on acoustic cavity resonance or [[Helmholtz resonance]] to produce an audible beep.<ref>{{Cite web | url=http://www.puiaudio.com/resources-white-papers-helmholtz.aspx |title = Design of a Helmholtz Chamber - PUI Audio &#124; A Projects Unlimited Company located in Dayton, Ohio}}</ref>

==Modern applications==
While technological advancements have caused buzzers to be impractical and undesirable{{Citation needed|date=May 2016}}, there are still instances in which buzzers and similar circuits may be used. Present day applications include:
* Novelty uses
* Judging panels
* Educational purposes
* [[Annunciator panel]]s
* Electronic [[metronome]]s
* [[Game show]] [[lock-out device]]
* [[Microwave oven]]s and other [[Major appliance|household appliances]]
* [[Sport]]ing events such as [[basketball]] games
* Electrical [[alarms]]
* Joy buzzer (mechanical buzzer used for pranks)

==See also==
* [[Alarm clock]]
* [[Alarm management]]
* [[Vehicle horn#Klaxon|Klaxon]]
* [[Vibrator (mechanical)]]
* [[Joy buzzer]]s
* [[UVB-76]], a Russian radio station that emits a characteristic buzzing sound and is also called The Buzzer.

==References==
{{Reflist}}

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[[Category:Electrical components]]
[[Category:Bells (percussion)]]