low-pressure sodium-vapour lamp
Quick Summary
A low-pressure sodium-vapor (LPS) lamp is an electric discharge lamp that uses ionized sodium for illumination, commonly employed for street lighting. Inside its discharge tube, neon and argon gas, along with metallic sodium, are present. When an electric current flows, it ionizes the gases, producing a red glow. This heat then vaporizes the sodium, which ionizes and emits a distinct, nearly monochrome yellow light. LPS lamps have been favored since the 1930s due to their energy efficiency and the fog-penetrating quality of their yellow light.12
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