Editing Keyboard technology (section)

== Keyboard switch matrix ==
[[File:Klavye_20.JPG|thumb|A close-up of a keyboard matrix circuit printed onto a flexible transparent [[Polyethylene terephthalate|PET]] sheet]]
{{Main|Keyboard matrix circuit}}
The keyboard switch matrix is often drawn with horizontal wires and vertical wires in a grid which is called a [[keyboard matrix (music)|matrix circuit]]. It has a switch at some or all intersections, much like a [[multiplexed display]].

=== Ghost keys ===
Almost all keyboards have only the ''switch'' (but no diode) at each intersection, which causes "ghost keys" and "key jamming" when multiple keys are pressed ([[rollover (key)|rollover]]). Certain, often more expensive, keyboards have a diode between each intersection, allowing the keyboard microcontroller to accurately sense any number of simultaneous keys being pressed, without generating erroneous ghost keys.<ref>{{Cite web |last=Dribin |first=Dave |title=Keyboard Matrix Help |url=http://www.dribin.org/dave/keyboard/ |access-date=21 January 2013 |archive-date=16 June 2013 |archive-url=https://web.archive.org/web/20130616044139/http://www.dribin.org/dave/keyboard/ |url-status=live }}</ref>