Home > News > Content

Incandescent Bulb The Thinner The Filament, The Greater The Resistance

May 25, 2017

1, who invented the Incandescent Bulb? Invented king Edison was invented in 1879.

2, incense lamp made of what principle made? The use of the principle of thermal effect of the current made. When incandescent work, the electrical energy is converted into internal energy and light energy.

3, the manufacture of incandescent materials can be divided into two categories? Conductors and insulators. Belong to the conductor are: iron screw buckle, tin block, tungsten wire, metal stent; are insulators are: glass isolation layer, glass pillars, glass bulbs.

4, incandescent filament is what material to do? Why is it glowing? Can I make filaments with other materials?

The filament of the Incandescent Bulb is made of tungsten with high melting point. When the current through the filament temperature of 2500 ℃ or more, filament fever to the incandescent state, issued a bright light, the melting point of other metals below the filament light when the temperature, easy to melt, so can not use other metal instead of tungsten wire filament.

5, with a long light bulb wall Why black? This is the filament after sublimation and condensate in the wall caused by the wall.

6, ordinary household Incandescent Bulb made of pear shape?

The filament of the bulb is made of metal tungsten. After power, the filament fever, the temperature up to 2500 ℃ or more. Metal tungsten sublimation at high temperatures, part of the metal tungsten particles from the filament surface ran out, attached to the inner wall of the lamp. Over time, the light bulb will turn black, reduce the brightness, affect the lighting.

Scientists according to the gas convection is a bottom-up feature, filled with a small amount of inert gas in the bulb, and the bulb made pear-shaped. In this way, when the inert gas in the bulb conveys, the black particles of the metal tungsten evaporate most of the gas particles to the top, the condensation deposited in the neck of the bulb, can keep the glass transparent, so that the brightness of the bulb is not affected.

7, why the glass bulb thickness uniform, and very thin? This is to prevent the glass bubbles inside and outside the heat uneven expansion of thermal expansion of glass bulbs.

8, light bulb buckle sets why the pattern? In order to increase the friction between the lamp cap and the lamp cap.

9, in the iron screw buckle and filament connection between the glass isolation layer what role? insulation.

10, why do you want to pump into a vacuum or filled with some inert gas? : Because vacuum and inert gas is hot bad conductor, can be insulated, but also to prevent the filament oxidation at high temperatures. Filled with some inert gas, can also reduce the tungsten wire sublimation.

11, when the vacuum bulb will be very broken, which is why?

The same token, when the vacuum bulb fell on the ground to break the moment, because the pressure inside the bulb is much smaller than the atmospheric pressure outside the bulb, the air around the bulb filled with vacuum part of the collision and issued a loud noise.

12, why is the incandescent filament spiral? This is mainly to reduce the filament's heat loss during energization to improve filament temperature and luminous efficiency.

13, can you use the appearance to determine the power of the lamp? can. The thicker the filament, the smaller the resistance, the rated voltage is the same, the greater the rated power of the lamp; filament finer, the greater the resistance, the smaller the rated power of the lamp.

14, why use a long Incandescent Bulb is usually smaller than the same specifications of the new Incandescent Bulb? This is because the filament sublimation and thinning, so that the lamp resistance becomes larger, through the filament current becomes smaller, when the voltage does not change, the actual power becomes smaller.

15, why summer at home to open high-power air-conditioning and other electrical appliances, the indoor light dim? This is because the total power in the home circuit increases, the trunk current increases, so that the shared voltage on the road to increase, then the voltage at both ends of the lamp becomes smaller, its actual power becomes smaller.

16 filament broken and then lap, why more bright? The filament of the Incandescent Bulb is broken and the length of the filament becomes shorter, the resistance becomes smaller, the voltage at both ends of the lamp is constant, and the actual power of the lamp becomes larger and the brightness becomes brighter. Since the actual power of the lamp is greater than the rated power at this time, the filament overheating is easier to blow.

17, when the light is turned on or closed when the radio will be "Kaka" noise? This noise is the circuit when the electromagnetic waves emitted by the radio received by the resulting.

18, how long is the life of incandescent?

The termination of the Incandescent Bulb life is mainly filament fracture. So the life of Incandescent Bulb depends mainly on the filament life. Incandescent work, the filament evaporates at high temperatures, the section gradually becomes smaller, to a certain extent there is a break. The higher the operating temperature, the faster the filament evaporates and the shorter the life span. Reduce the filament operating temperature, can make the filament evaporation rate significantly reduced, it can greatly extend the filament life. But the filament operating temperature is reduced, the luminous efficiency will be significantly reduced. Therefore, the manufacturer after weighing the life and light efficiency, to determine a suitable filament operating temperature, working at this temperature, the average filament life of Incandescent Bulb is about 1000 hours.

19, bulb broken wire What are the reasons?

The direct cause of the broken wire is that the filament is blown at high temperatures. For a variety of reasons, the temperature of the entire filament during incandescent work can not be completely uniform and everywhere. When a place temperature is too high, where the filament (called hot spots) due to higher temperature, faster evaporation. After a certain period of time, the hot cross section becomes smaller and the resistance increases, followed by higher temperatures and faster evaporation. So the cycle, not how long, hot spots at the filament will be broken and become a breakpoint, resulting in lamp life end. Qualified light bulbs work at rated voltage, some light bulbs short life in 500 hours or less, long up to 1500 hours or more.

Hot spot is the root cause of the normal broken wire, to extend the life of Incandescent Bulb, the key is to delay the hotspots before the hotspot hotspot development speed. It is clear that the broken wire is not caused by electric power damage. Broken wire is completely heat damage. To make the filament burned in an instant, the filament temperature must be much higher than the normal working temperature. The inrush current of the lamp is very large, but after all it is the instantaneous current of the cold state, it disappears once the filament temperature reaches the normal operating temperature. That is, the instantaneous high current is present in the filament before the high temperature work. So the Incandescent Bulb current shock is not the main reason for broken wire. As for many incandescent broken wire occurred in the light moment, it is only a surface phenomenon Bale. These lights in the light burned instantly, the filament of the hot spots have been prominent, life is nearing the end, even in the normal state, but also not much time the filament hot spots will break.

For the user, the real way to delay the development of hotspots, is to reduce the operating voltage of the lamp to reduce the filament operating temperature, so that the filament evaporation rate, which effectively extend the filament life. In the case of high voltage, this approach is not only effective but also necessary. In some places, the night lighting line voltage to 240 volts, this time the average life expectancy of incandescent light will only about 300 hours. If the voltage can be reduced to 200 volts, the average life of the new bulb can be extended to about 3600 hours. But with the lamp operating voltage is reduced, the brightness of the lamp also will be reduced to normal when about 70% or less.