Was (wer) ist radio buttons - definition
![[[Frequency]] spectrum of a typical modulated AM or FM radio signal. It consists of a component ''C'' at the [[carrier wave]] frequency <math>f_c</math> with the information ([[modulation]]) contained in two narrow bands of frequencies called [[sideband]]s (''SB'') just above and below the carrier frequency.](https://commons.wikimedia.org/wiki/Special:FilePath/Modulated radio signal frequency spectrum.svg?width=200 "[[Frequency]] spectrum of a typical modulated AM or FM radio signal. It consists of a component ''C'' at the [[carrier wave]] frequency <math>f_c</math> with the information ([[modulation]]) contained in two narrow bands of frequencies called [[sideband]]s (''SB'') just above and below the carrier frequency.")
![Radio communication. Information such as sound is converted by a transducer such as a [[microphone]] to an electrical signal, which modulates a [[radio wave]] produced by the [[transmitter]]. A receiver intercepts the radio wave and extracts the information-bearing modulation signal, which is converted back to a human usable form with another transducer such as a [[loudspeaker]].](https://commons.wikimedia.org/wiki/Special:FilePath/Signal processing system.png?width=200 "Radio communication. Information such as sound is converted by a transducer such as a [[microphone]] to an electrical signal, which modulates a [[radio wave]] produced by the [[transmitter]]. A receiver intercepts the radio wave and extracts the information-bearing modulation signal, which is converted back to a human usable form with another transducer such as a [[loudspeaker]].")
![Volkswagen's RNS-510 receiver supports [[Sirius Satellite Radio]].](https://commons.wikimedia.org/wiki/Special:FilePath/SiriusXM Display on Volkswagen's RNS-510 Receiver.png?width=200 "Volkswagen's RNS-510 receiver supports [[Sirius Satellite Radio]].")
![shows its own photo]]](https://commons.wikimedia.org/wiki/Special:FilePath/Wireless network.jpg?width=200 "shows its own photo]]")
Wikipedia
A radio button or option button is a graphical control element that allows the user to choose only one of a predefined set of mutually exclusive options. The singular property of a radio button makes it distinct from checkboxes, where the user can select and unselect any number of items.
Radio buttons are arranged in groups of two or more and displayed on screen as, for example, a list of circular holes that can contain white space (for unselected) or a dot (for selected). Each radio button is normally accompanied by a label describing the choice that the radio button represents. The choices are mutually exclusive; when the user selects a radio button, any previously selected radio button in the same group becomes deselected (making it so only one can be selected). Selecting a radio button is done by clicking the mouse on (or touching the screen over) the button, or the caption, or by using a keyboard shortcut.
It is possible that initially none of the radio buttons in a group are selected. This unselected state cannot be restored by interacting with the radio button widget, though it may be possible through other user interface elements. When used in an HTML form, if no button in a group is checked, then no name–value pair is passed when the form is submitted. For example, for a radio button group named Sex with the options Male and Female, the variable Sex would not be passed, even with a blank value.
