Editing Touchscreen (section)

====Surface capacitance====
In this basic technology, only one side of the insulator is coated with a conductive layer. A small voltage is applied to the layer, resulting in a uniform electrostatic field. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel. As it has no moving parts, it is moderately durable but has limited resolution, is prone to false signals from parasitic [[capacitive coupling]], and needs [[calibration]] during manufacture. It is therefore most often used in simple applications such as industrial controls and [[interactive kiosk|kiosks]].<ref>{{cite web|url=http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=18592|title=Please Touch! Explore The Evolving World Of Touchscreen Technology|publisher=electronicdesign.com|access-date=2009-09-02|url-status=dead|archive-url=https://web.archive.org/web/20151213043947/http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=18592|archive-date=2015-12-13}}</ref>

Although some standard capacitance detection methods are projective, in the sense that they can be used to detect a finger through a non-conductive surface, they are very sensitive to fluctuations in temperature, which expand or contract the sensing plates, causing fluctuations in the capacitance of these plates.<ref>{{cite web|url=https://www.electronics-tutorials.ws/capacitor/cap_4.html|title=formula for relationship between plate area and capacitance|date=26 July 2013 }}</ref> These fluctuations result in a lot of background noise, so a strong finger signal is required for accurate detection. This limits applications to those where the finger directly touches the sensing element or is sensed through a relatively thin non-conductive surface.