
74 Electrical Discharge Lamps
Figure 3.35. Electrode of a low-pressure sodium vapor discharge lamp.
80
700600
Low-Pressure Sodium
Wavelength (nm)
500400
0
20
40
60
80
100
Figure 3.36. Emission spectrum of a low-pressure sodium vapor discharge lamp.
Table3.9. Table with Indicative Values and Information about the General
Characteristics of the Low-Pressure Sodium Vapor Lamp
Gas ll Inner: 1% Ar in Ne|Na Outer: Vacuum
Luminous ux 4800 lm (100 h) 4560 lm (end of lifetime)
Efcacy 126 lm/W (100 h) 120 lm/W (end of lifetime)
Color temperature and CRI CCT: 1700 K CRI: Ra = 0
Color coordinates CCx: 0.574 CCy: 0.425
Average lifetime 20,000 ...