In the process of manufacturing incandescent lamps, a big leap forward was the addition of very aggressive additives to the filler gases – iodine or bromine halogens..
The point is that the temperature of the lamp filament cannot exceed a certain limit. Above this limit, the tungsten from which the filament is made begins to evaporate intensively.
The evaporated tungsten deposits as a dark coating on the lamp walls, which makes the lamp dimmer. The filament becomes thinner, due to which the lamp quickly burns out.
In a halogen lamp, the evaporating metallic tungsten does not settle on the relatively cold walls of the bulb, but forms a volatile compound with the halogen.
Tungsten halide circulates through the volume of the flask, and, reaching a red-hot tungsten filament, decomposes into its original components. The halogen returns to the cycle, and the metallic tungsten partially settles on the filament, and partially remains in the form of an “atmosphere” around the filament.
The increased concentration of tungsten vapors in the immediate vicinity of the thread sharply slows down its further evaporation, just as a humid atmosphere does not allow wet laundry to dry. As a result, the thread is not thinned, and the glass remains transparent..
But that doesn’t stop the benefits of halogens. Now the thread can be heated more strongly, almost to the melting point of tungsten – after all, its evaporation is slowed down. This makes it possible to bring the color of their radiation closer to the natural solar.
The most successfully bright, beautiful, saturated light of halogen lamps is characterized by the epithet “juicy”. Note also that this “juiciness” does not dry out throughout the life of the lamps. And the life of this service is twice as long as a conventional incandescent lamp with a similar power..
The light output of halogen lamps is twice that of conventional incandescent lamps. From this it follows that replacing conventional lamps with halogen lamps will significantly reduce energy consumption..
Halogen lamps are of two types: high-voltage, operating under a voltage of 220 V and low-voltage, for 6, 12, 24 and 36 V. More often, 12-volt lamps are used..
The advantages of low-voltage lamps are obvious – increased safety, especially in high humidity conditions, such as in the bathroom and a longer life.
The average service life of 220-volt lamps is 2000 hours, 12-volt lamps – 4000. However, they require a transformer that reduces the voltage from 220 to 12 V and separate wiring.
The disadvantage of halogen lamps is their increased sensitivity to power surges, so it is advisable to turn them on through a voltage stabilizer.
To achieve the maximum efficiency of the lamp, it is advisable to use it at the full power declared by the manufacturer. However, its brightness can be adjusted using standard dimmers..
By lowering the lamp power, you can reduce or even disable the operation of the halogen cycle, and it will begin to work like a normal incandescent lamp. To restore the work of halogens and remove metal particles of tungsten that have settled on the walls of the flask, it is enough to turn on the lamp at full power for a few minutes.
Of the disadvantages of halogen lamps, it should also be noted that the surface temperature of the bulb can reach 500 ° C, therefore, fire safety standards should be strictly observed when installing lamps. Do not touch the turned on or insufficiently cooled lamp, as this can lead to serious burns.
And the cooled lamp should not be taken with bare hands. This leaves greasy spots on the lamp bulb, after switching on the fat is charred under the influence of high temperature, black particles of coal absorb heat and become very hot. Local overheating may cause the bulb to burst and the lamp to explode.
The lamp should be handled using clean cloth gloves, a piece of clean cloth, or at least a paper towel. If the flask is stained with something, wipe it with alcohol.
Recently, low voltage halogen lamps with reflectors have become widespread. In these lamps, up to two thirds of the infrared radiation of the lamp is reflected by a translucent mirror, so the illuminated objects are less heated. Cooled lamps with a reflector can be handled.
The high color temperature of halogen lamps is not always a good thing – there is an excess of ultraviolet radiation in their spectrum, which is harmful to health. Therefore, when buying a halogen lamp, pay special attention to whether it is equipped with UV protection.