PHILIPS LIGHTING 120550 320W 120/277/347V Philips Advance Core & Coil HID Metal Halide Ballast, Black

ADVANCE® HID Lamp Ballasts are available to operate the wide variety of mercury, metal halide, high pressure sodium and low pressure sodium lamps available in today’s marketplace. Like ¿uorescent, HID lamps are electric discharge lamps. Light is produced by an arc discharge between two electrodes located at opposite ends of an arc tube within the lamp’s outer glass envelope. The ballast is the lamp’s power supply; its purpose is to provide proper starting and operating voltage and current to initiate and sustain this arc.