View source for Push-button

{{Short description|Mechanism to control a machine or process}}
{{Othermeanings|Button (disambiguation)}}
{{Infobox electronic component
| name              = Push-button
| image             = Arcade video game buttons.jpg
| caption           = Generic [[arcade game]] buttons
| type              = [[Switch]]
| working_principle =
| invented          =
| first_produced    =
| pins              =
| symbol            = [[File:IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (57).svg]]
| symbol_caption    =
}} 

A '''push-button''' (also spelled '''pushbutton''') or simply '''button''' is a simple [[electrical switch|switch]] mechanism to control some aspect of a [[machine]] or a [[Process (engineering)|process]]. Buttons are typically made out of hard material, usually [[plastic]] or [[metal]].<ref>{{cite web|title=Push buttons and much more|url=http://www.thebuilderssupply.com/Push-buttons-and-much-more_b_14.html|publisher=thebuilderssupply.com|access-date=11 April 2013}}</ref> The surface is usually flat or shaped to accommodate the human finger or hand, so as to be easily depressed or pushed. Buttons are most often [[Switch#Biased switches|biased switches]], although many un-biased buttons (due to their physical nature) still require a [[Spring (device)|spring]] to return to their un-pushed state.

Terms for the "pushing" of a button include '''pressing''', '''depressing''', '''mashing''', '''slapping''', '''hitting''', and '''punching'''.

== Uses ==
[[File:Calculator delete button.jpg|thumb|Buttons on a handheld [[calculator]]]]
[[File:StreetCrossingButton-2022Dec10.webm|thumb|Push-button for a crosswalk in use in [[Japan]], 2022]]

The "push-button" has been utilized in [[calculators]], [[push-button telephone]]s, [[kitchen appliances]], and various other mechanical and electronic devices, home and commercial.

In industrial and commercial applications, push buttons can be connected together by a mechanical linkage so that the act of pushing one button causes the other button to be released. In this way, a stop button can "force" a start button to be released. This method of linkage is used in simple manual operations in which the machine or process has no [[electrical circuit]]s for control.

Red pushbuttons can also have large heads (called mushroom heads) for easy operation and to facilitate the stopping of a machine. These pushbuttons are called [[emergency stop]] buttons and for increased safety are mandated by the electrical code in many jurisdictions. This large mushroom shape can also be found in buttons for use with operators who need to wear [[glove]]s for their work and could not actuate a regular [[flush-mount]]ed push button.

[[File:Knopka 8 ugolnik.jpg|thumb|Button shaped as an octagon]]

As an aid for operators and [[End-user|user]]s in industrial or commercial applications, a pilot light is commonly added to draw the attention of the user and to provide [[feedback]] if the button is pushed. Typically this light is included into the center of the pushbutton and a [[lens (optics)|lens]] replaces the pushbutton hard center disk. The source of the energy to illuminate the light is not directly tied to the contacts on the back of the pushbutton but to the action the pushbutton controls. In this way a start button when pushed will cause the process or machine operation to be started and a secondary contact designed into the operation or process will close to turn on the pilot light and signify the action of pushing the button caused the resultant process or action to start.

To avoid an operator from pushing the wrong button in [[error]], pushbuttons are often [[color-coded]] to associate them with their function. Commonly used colors are red for stopping the machine or process and green for starting the machine or process.

In [[popular culture]], the phrase "the button" (sometimes capitalized) refers to a (usually fictional) button that a military or government leader could press to launch [[nuclear weapon]]s.

=== Scram and scramble switches ===
Akin to [[fire alarm]] switches, some big red buttons, when deployed with suitable visual and audible warnings such as flashing lights and sirens for extreme exigent emergencies, are known as "scram switches" (from the slang term  [[wikt:scram|scram]], "get out of here"). Generally, such buttons are connected to large scale functions, beyond a regular fire alarm, such as automated shutdown procedures, complete facility power cut, fire suppression like halon release, etc.

A variant of this is the scramble switch which triggers an alarm to activate emergent personnel to proactively attend to and go to such disasters. An air raid siren at an air base initiates such action, where the fighter pilots are alerted and "[[Scrambling (military)|scrambled]]" to their planes to defend the base.

==History==
Push buttons were invented sometime in the late 19th century, certainly no later than 1880.<ref name=":0">{{Cite web |last=Wills |first=Matthew |date=2021-05-11 |title=When the Push Button Was New, People Were Freaked |url=https://daily.jstor.org/when-the-push-button-was-new-people-were-freaked/ |access-date=2023-01-09 |website=JSTOR Daily |language=en-US}}</ref>  The name came from the French word {{Lang|fr|bouton}} (something that sticks out), rather than from the kind of [[Button|buttons]] used on clothing.<ref name=":0" />  The initial public reaction was curiosity mixed with fear, some of which was due to widespread fear of electricity, which was a relatively new technology at the time.<ref name=":0" />

==See also==
{{div col|colwidth=18em}}
* [[Event-driven programming]]
* [[Button accordion]]
* [[Button (computing)]]
* [[Keyboard (computing)]]
* [[Panic button]]
* [[Placebo button]]
* [[Push-button telephone]]
* [[Reset button]]
* [[Shutter button]]
* [[Turbo button]]
{{div col end}}

==References==
{{Reflist}}

==Further reading==

* Rachel Plotnick, ''Power Button: A History of Pleasure, Panic and the Politics of Pushing'', MIT Press, 2018, {{isbn|9780262038232}}, reviewed in David Trotter, "Making doorbells ring", ''[[London Review of Books]]'' [https://www.lrb.co.uk/v40/n22/david-trotter/making-doorbells-ring 22 November 2018]

== External links ==
{{commons category|Push buttons}}
* [https://demonstrations.wolfram.com/SpringReturnButton/ Spring Return Button] by Sándor Kabai, [[The Wolfram Demonstrations Project]].

{{Switches}}

[[Category:Human–machine interaction]]
[[Category:Switches]]