A button ( Italian tasto , Latin clavis ), a push button or a button is a control element that is actuated by pressing and automatically returns to the starting position when released. A mechanical spring is usually used for this. Small buttons are also often referred to as buttons (especially if they are round).
A group of keys is called a keypad . Keypads that are used to enter words or numbers are called keyboards . Keyboard instruments have a keyboard . Keys that are operated with the feet are called pedals .
Latching buttons do not belong to the keys in the strict sense, but to the switches .
The oldest keys are found on the keyboard instruments . When the piano one example, with the key on a leather strap levers set in motion, of a hammer against the string strikes. On the organ , a valve is opened to the associated organ pipe .
On the typewriter , most keys hit a type against the ribbon using levers and rods. But there are also the Shift , which lifts the roller to reach the capital letters and the shift lock that locks the Shift key, so prevents them back on again.
In the case of special electrical safety requirements, there are foot-operated pushbuttons that act on a switching contact with water via a hose and a membrane, which only consist of a hollow rubber body.
Electric buttons are mostly mechanical buttons or pushbuttons in which contacts are moved when actuated . Depending on the intended use, the contacts are closed when actuated, i.e. brought into contact with one another ( make contact ), or opened ( break contact ). If a permanent change of state is to be brought about by a button, for example to switch a light on or off, a button circuit is used. In this case, tapping a button causes an electrical pulse to change the switching status of a connected impulse relay (e.g. light on or light off ), which is stored mechanically or electronically until the next pulse, i.e. the next time the button is tapped becomes.
Industrial buttons often have both types of contact pairs - they have a normally open contact and an opener that is electrically separated from it.
Instead of solid pieces of metal, membrane keys use conductor paths on foils. The cover sheet is often equipped with a spring-loaded disc spring. When actuated, the spring also establishes the electrical connection. The jump function facilitates defined actuation. Membrane keys are only suitable for switching small currents. They are used in membrane keyboards and cell phones .
Silicon keypads (also known as conductive rubber buttons ) consist of a conductive contact pill that presses on a comb-like interlocking structure of conductive surfaces (for example on a circuit board ). They are used in computer keyboards, remote controls , cell phones and in individual buttons for PCB assembly.
Keys for electronic musical instruments not only report the fact that the key has been pressed, but also provide information on how hard or fast it was pressed. This is done, for example, by measuring the time that is measured between the release of two consecutive buttons when the button is pressed. As with the mechanical piano, this makes it possible to make the volume and duration dependent on the intensity of the key stroke. This property of electronic keyboard instruments is known as touch response.
Several keys which are arranged in a certain way ( layout ) form a keyboard . The keys are labeled to send different characters or to trigger commands . Well-known layouts are the typewriter keyboard and the telephone keyboard . The computer keyboards are derived from the typewriter keyboards. Membrane keyboards on machines often have a function-specific design. Electronic keyboards convert the parallel data stream into serial data so that they can be transmitted over one or a few lines.
Thanks to their robust design, emergency stop buttons force the safe separation of one or more electrical circuits. When actuated, they often do not return to their original position, but have to be reset by pulling or turning or using a key.
So-called vandalism buttons (vandal-proof buttons) offer a high level of security against willful destruction, even when tools are used. You can find them u. a. in elevators or other public facilities.
Sensor keys have no moving parts and react to pressure or approach with a finger by changing electrical or non-electrical parameters.
Types of sensor keys:
- Capacitive keys react to the change in capacitance or interference coupling caused by the approach of the finger to a sensor electrode. Capacitive buttons require an auxiliary voltage.
- Piezo buttons contain a piezo element which generates an electrical voltage when the pressure changes. This voltage is used to control an electronic switch. Piezo buttons do not require any auxiliary energy.
- Touchscreens are two-dimensional, freely programmable, transparent keypads in front of a screen or computer monitor . They mostly work according to the principle of capacitive keys, with the sensor electrodes consisting of wires that are incorporated orthogonally to one another.
- Touchpads work just like touchscreens and serve as a replacement for a computer mouse in notebooks .
- Softkeys are fields on a touchscreen to which changing functions are assigned via software. Such operated with a computer mouse virtual buttons on a screen are often referred to as button (english button called).
- Bell button with which visitors to a property draw attention to themselves; also as part of a bell system
- Eject button , button for ejecting a data carrier in computers and hi-fi systems
- Morse key , key for the precise generation of Morse code
- Signal button , telephone button with special functions
- Blade tip of foil or epee in fencing for electronic hit display
- Brockhaus' Kleines Konversations-Lexikon . 11th edition. FA Brockhaus, Leipzig 1911 ( zeno.org [accessed October 8, 2019] Lexicon entry “Taste”).
- Horst Völz: The human-technology system . Physiological, physical and technical basics; Software and hardware. expert verlag, 1999, ISBN 978-3-8169-1643-7 , p. 150 ( google.de [accessed on September 20, 2016]).
- https://www.wissen.de/lexikon/sensortaste Communication from Konradin Medien GmbH on the term Sensortaste, accessed on April 9, 2020