filament rather than the tungsten becoming deposited on the glass. A 300-watt tubular halogen bulb operated at full power quickly reaches a temperature of about 540 C, while a 500-watt regular incandescent bulb operates at only 180 C and a 75-watt regular incandescent at only 130 C.

The bulb must be made of fused silica (quartz) or a high-melting-point glass (such as aluminosilicate glass). Since quartz is very strong, the gas pressure can be higher which