INTRODUCTION TO COLD CATHODE Cold Cathode Versus Neon, Fluorescent, and Fiber Optic WHAT'S THE DIFFERENCE BETWEEN COLD Detail of a 25mm cold CATHODE AND NEON? cathode lamp. The electrode is a virtually indestructible Although both cold cathode and neon create light by iron thimble that allows for instant lamp starting, 50,000- the same principle, cold cathode lamps operate on hour life, and the ability to significantly higher currents, utilize more efficient lamp dim without any special dimming ballasts. Cold color coatings, and are more than twice the diameter cathode lamps produce up of neon tubing. Cold cathode also provides up to five to 5 times more light than neon tubes. times the light output of neon with the same choice of colors. Cold cathode lamps are also far easier to Detail of a 12mm neon tube. Neon tubes are low bright- install and, are much less fragile. Unlike neon, each ness and small diameter and cold cathode system from Cathode Lighting Systems are ideally suited for signs and graphics but not for carries a full UL and C-UL listing. general illumination. WHAT'S THE DIFFERENCE BETWEEN COLD CATHODE AND FLUORESCENT? The technical name for a standard fluorescent lamp is hot cathode. The coated tungsten coil within the lamp produces electrons to support the lamp's gas discharge in a process called thermionic emission. This means that in order to produce The interior of a standard fluorescent lamp. A tungsten electrons, the coated coil must be red hot (approximately coil is coated within emissive 900˚ C). When the emissive material that coats the coil is con- material. Lamp life is typically 15,000 hours and is reduced sumed, the lamp ceases to operate. These lamps require by 3 hours each time lamps special ballasts if dimming is required. Conversely, a cold are turned on. cathode electrode is a rugged iron thimble that does not operate in a thermionic manner. At an operating temperature of approximately 200˚ C, the electrode is relatively cold, hence the term cold cathode. The typical lamp life of a fluorescent lamp is 15,000 hours with 3 TYPICAL EXPECTED LAMP LIFE: COLD CATHODE VS. FLUORESCENT 100% hours of lamp life lost each time lamps are 90% turned on. 80% 70% COLD CATHODE The chart at right illustrates the typical 60% LAMPS lamp life of a cold cathode lamp versus 50% FLUORESCENT a fluorescent lamp based on testing a 40% large batch of each type of lamp. LAMPS Notice that 50% of the fluorescent lamps 30% have already failed prior to reaching 20% their rated life. 10% PERCENT OF LAMPS STILL OPERATIONAL 0% 0 5 10 15 20 25 30 35 40 45 50 HOURS OF OPERATION (IN THOUSANDS) © 2002 Cathode Lighting Systems Inc. 8020 Queenair Drive, Gaithersburg, MD 20879 • ph: 301 921 4120 • fax: 301 963 3050 e-mail: [email protected] • website: www.CathodeLightingSystems.com 5.