Editing Diode (section)

===Temperature measurements===
A diode can be used as a [[temperature]] measuring device, since the forward voltage drop across the diode depends on temperature, as in a [[silicon bandgap temperature sensor]]. From the Shockley ideal diode equation given above, it might ''appear'' that the voltage has a ''positive'' temperature coefficient (at a constant current), but usually the variation of the [[Saturation current|reverse saturation current]] term is more significant than the variation in the thermal voltage term. Most diodes therefore have a ''negative'' temperature coefficient, typically −2 mV/°C for silicon diodes. The temperature coefficient is approximately constant for temperatures above about 20 [[kelvin]]. Some graphs are given for 1N400x series,<ref>{{cite web |url=http://www.cliftonlaboratories.com/1n400x_diode_family_forward_voltage.htm |title=1N400x Diode Family Forward Voltage |website=cliftonlaboratories.com |access-date=2013-12-19 |archive-url=https://web.archive.org/web/20130524153406/http://www.cliftonlaboratories.com/1n400x_diode_family_forward_voltage.htm |archive-date=2013-05-24}}</ref> and CY7 cryogenic temperature sensor.<ref>[http://www.omega.com/Temperature/pdf/CY7.pdf Cryogenic Temperature Sensors]. omega.com</ref>