A push-button (also spelled pushbutton) or simply button is a simple
switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
mechanism to control some aspect of a
machine or a
process
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:
Business and management
*Business process, activities that produce a specific se ...
. Buttons are typically made out of hard material, usually
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
or
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
.
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
biased switches, although many un-biased buttons (due to their physical nature) still require a
spring
Spring(s) may refer to:
Common uses
* Spring (season)
Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...
to return to their un-pushed state.
Terms for the "pushing" of a button include pressing, depressing, mashing, slapping, hitting, and punching.
Uses
![Calculator delete button](https://upload.wikimedia.org/wikipedia/commons/a/ab/Calculator_delete_button.jpg)
The "push-button" has been utilized in
calculators,
push-button telephone
The push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to having a rotary dial as in earlier telephone instruments.
Western Electric experimented as early as 1941 with methods of using mech ...
s,
kitchen appliances
A home appliance, also referred to as a domestic appliance, an electric appliance or a household appliance, is a machine which assists in household functions such as cooking, cleaning and food preservation.
Appliances are divided into three ...
, 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 circuits 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
A kill switch, also known as an emergency stop (E-stop), emergency off (EMO) and as an emergency power off (EPO), is a safety mechanism used to shut off machinery in an emergency, when it cannot be shut down in the usual manner. Unlike a normal ...
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
gloves for their work and could not actuate a regular
flush-mounted push button.
![Knopka 8 ugolnik](https://upload.wikimedia.org/wikipedia/commons/a/a6/Knopka_8_ugolnik.jpg)
As an aid for operators and
users 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
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements ...
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
An error (from the Latin ''error'', meaning "wandering") is an action which is inaccurate or incorrect. In some usages, an error is synonymous with a mistake. The etymology derives from the Latin term 'errare', meaning 'to stray'.
In statistics ...
, pushbuttons are often
color-coded
A color code is a system for displaying information by using different colors.
The earliest examples of color codes in use are for long-distance communication by use of flags, as in semaphore communication. The United Kingdom adopted a color c ...
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
Popular culture (also called mass culture or pop culture) is generally recognized by members of a society as a set of practices, beliefs, artistic output (also known as, popular art or mass art) and objects that are dominant or prevalent in a ...
, the phrase "the button" (sometimes capitalized) refers to a (usually fictional) button that a military or government leader could press to launch
nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...
s.
Scram and scramble switches
Akin to
fire alarm
A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related or general notification emergency, emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also ...
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
scram
A scram or SCRAM is an emergency shutdown of a nuclear reactor effected by immediately terminating the fission reaction. It is also the name that is given to the manually operated kill switch that initiates the shutdown. In commercial reactor ...
, "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 "
scrambled" to their planes to defend the base.
See also
*
Event-driven programming
In computer programming, event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions (mouse clicks, key presses), sensor outputs, or message passing from other programs or thr ...
*
Button accordion
A button accordion is a type of accordion on which the melody-side keyboard consists of a series of buttons. This differs from the piano accordion, which has piano-style keys. Erich von Hornbostel and Curt Sachs categorize it as a free reed ae ...
*
Button (computing)
In computing, the term button (sometimes known as a ''command button'' or '' push button'') refers to any graphical control element that provides the user a simple way to trigger an event, like searching for a query at a search engine, or t ...
*
Keyboard (computing)
A computer keyboard is a peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology, ...
*
Panic button
A panic alarm is an electronic device that can easily be activated to request help during an emergency situation where danger to persons or property exists. It is designed to minimize time until assistance can arrive.
A panic alarm is freque ...
*
Placebo button A placebo button is a push-button or other control that appears to have functionality but has no physical effect when pressed. Such buttons can appear to work, by lighting up or otherwise reacting, which rewards the user by giving them an illusion ...
*
Push-button telephone
The push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to having a rotary dial as in earlier telephone instruments.
Western Electric experimented as early as 1941 with methods of using mech ...
*
Reset button
In electronics and technology, a reset button is a button that can reset a device. On video game consoles, the reset button restarts the game, forfeiting the player's unsaved progress. On personal computers,On IBM mainframes reset neither c ...
*
Shutter button
*
Turbo button
On IBM PC compatible computers, the turbo button selects one of two run states: the default "turbo" speed or a reduced speed closer to the Intel 8086 CPU. It was relatively common on computers using the Intel 80286, Intel 80386 and Intel 80486 ...
References
Further reading
* Rachel Plotnick, ''Power Button: A History of Pleasure, Panic and the Politics of Pushing'', MIT Press, 2018, , reviewed in David Trotter, "Making doorbells ring", ''
London Review of Books'
22 November 2018
External links
Spring Return Buttonby Sándor Kabai,
The Wolfram Demonstrations Project
The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-size) interactive programs called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields. It is hos ...
.
{{Switches
Human–machine interaction
Switches