What is a High Pressure Sodium (HPS) Lamp?
Invented in 1931, the high-pressure sodium lamp has a transparent discharge tube filled with a gas and sodium mixture (the conductor.) An electric current vaporizes the conductor causing it to glow, which results in the emission of light and heat. A current regulating device, commonly known as the ballast, is required to limit and stabilize the current passing through the lamp, greatly reducing the loss of energy in the form of heat. The ballast also prevents overdriving of the lamp, resulting in longer lamp life.
