Neon Lamp(redirected from Neon tubes)
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a low-pressure gas-discharge light source in which visible radiation is produced by a discharge in a neon atmosphere. The best-known neon lamps are the glow-discharge signal lamps, in which the orange-red luminescence of the discharge regions adjacent to the cathode is used. The lamps are filled with a mixture of neon and helium. To decrease the discharge voltage, a small quantity of argon is introduced into the gas mixture, and the surface of the cathode may be coated with a thin layer of an activating substance. The lamps operate on alternating or direct current. Their power is 0.01 to 10 watts (W), their light flux is 0.02 to 5 lumens (lm), and their current ranges from fractions of a milliampere (mA) to 20–30 mA. In cold-cathode neon lamps used in advertising (fluorescent lamps), the glow of the positive column of the glow discharge is used.
Neon arc lamps with a heater cathode are used as airport beacons; their power is of the order of 500 W, and their luminous efficiency is up to 10 lm/W. They operate reliably at ambient temperatures from —40° to 40°C. The luminous efficiency of mercuryless, fluorescent neon arc lights (about 25 lm/W) exceeds that of red-fluorescent mercury lamps by a factor of 3 and is determined by the visible radiation of the positive discharge column and the fluorescence of a phosphor layer (such as Y2O3 or activated europium) deposited on the walls of the tube. The lighting and electrical parameters of fluorescent neon lamps, in contrast to those of fluorescent mercury lamps, do not depend on the ambient temperature.
V. V. FEDOROV