A cold cathode is a cathode (an electrode that emits electrons) that is not electrically heated by a filament.{clarify|reason=Cathode definition/CCD/(electrons enter device) is external viewpoint, but electron emission is internal viewpoint|date=September 2014} It is used in gas-discharge lamps, such as neon lamps, discharge tubes, and some types ... Found on http://en.wikipedia.org/wiki/Cold_cathode