Conventional & Cold Cathode Fluorescent Lighting
Conventional Fluorescent Lighting
Fluorescent lighting operates at several times the efficiency of incandescent lamps and is important for energy conservation, especially in photovoltaic power systems where electricity generation and storage costs are relatively high. Even small improvements in lamp efficiency can offset substantial capital and operating expenses for solar lighting systems.
Conventional fluorescent lamps apply a voltage between heated electrodes located at each end of the tube, creating an electric arc discharge. Special gasses in the tube emit ultraviolet light that stimulates fluorescence of the phosphors lining the inside of the tube.
Correct electrode temperature is crucial to the longevity of the lamps which are rapidly degraded by variations from their optimum input voltage and ambient temperature. This is a major problem for extra-low-voltage lighting systems using storage batteries.
Nominal 12 volt batteries typically reach 15 volts during boost phases and below 11 Volts when discharged. Many fluorescent lamps overheat and fail if operated at 15 volts for more than a few minutes. Low voltages damage the tube electrodes due to insufficient heating, resulting in internal tube blackening and a decline in phosphor efficiency.
Even under ideal conditions, the electrodes slowly accumulate damage from the electric arc discharge. Material is slowly vaporised from the electrodes and deposited on the inside of the tube, degrading the phosphors and causing most of the characteristic decline in light output as the tube ages.
The heated electrodes are also a substantial contribution to the energy consumption of the lamp. Consequently, fluorescent lamp efficiency is generally a function of size. Large lamps are more efficient, in part because a smaller proportion of energy is used to heat the electrodes in a longer tube.
Cold Cathode Fluorescent Lighting
Cold cathode fluorescent tubes operate at a much higher voltage and lower current than conventional fluorescent lamps. The higher voltage overcomes the need to heat the tube while the lower arc current greatly extends the life of the discharge electrodes.
Dispensing with the wasteful heated electrodes allows high efficiency to be achieved in a small lamp. Cold cathode lamps are typically 10 to 30 percent more efficient than a comparable hot cathode fluorescent lamp.
Cold cathode lights have a life expectancy more than twice that of typical compact fluorescent lamps and do not suffer accelerated degradation with variations in supply voltage.
See our range of cold cathode lights.
Dimming represents one of the most effective ways to reduce power consumption. While a bright light is required for some activities there are often occasions where a much lower lighting level would be sufficient or desirable.
Cold cathode lamps can be dimmed to any point without damage. Without the need for precise electrode temperature the cold cathode lamp can be operated at any desired brightness up to their maximum rating. They can even be continuously operated in flashing applications that would destroy a conventional fluorescent lamp in a day.
Rainbow Power Company's cold cathode lamps are fully dimmable by reducing the input voltage with a simple adjustable resistor. Although there are some losses involved in using a resistive controller they are kept to a minimum because the current diminishes quite rapidly as the voltage declines.
Our cold cathode lamps are designed to be similar in size to a standard incandescent lamp bulb. This means they are small enough to be used in virtually any lighting appliance fitted with a 27 mm Edison socket.