In: Anatomy and Physiology
What is dark current? What turns dark current on, and what turns it off?
Dark current is residual current produced by a photoelectric device when not illuminated. It consists of the charge generated in the detector when no outside radiation is entering the detector.
Dark current is turned on by the thermal excitation of electrons and is a temperature dependent process.
Dark current can be turned off by cooling the charge coupled device by liquid nitrogen produced as a result of thermal generation at room temperature.