rise up into the air and dissipate into the atmosphere. Spark gaps which only intermittently produce short spark bursts are also minimally hazardous because the volume of ions generated is very small. Arcs can also produce a broad spectrum of wavelengths spanning the visible light and the invisible ultraviolet and infrared spectrum. Very intense arcs generated by means such as arc welding can produce significant amounts of ultraviolet radiation which is damaging to the cornea of the observer. These arcs should only be observed through special dark filters which reduce the arc intensity and shield the observer's eyes from the ultraviolet rays. See also Arc transmitter List of light sources Marx generator Spark gap Vacuum arc Paschen's law References External links "High Voltage Arcs and Sparks" Videos of 230 kV 3-phase "Jacobs Ladder" and unintentional 500 kV power arc High Voltage Arc Gap Calculator to calculate the length of an arc knowing the voltage or vice versa Electric heating Electrical discharge in gases Articles containing video clips