What is the interface between light bulb and spotlight in Japan?

Old kerosene lamps use cotton wick, and its lamp holder is usually copper, and the lamp holder and lamp tube for wind protection are made of glass.

There are many claws around the lamp holder, and there is a pinion next to it to control the cotton rope to rise or fall.

The lower part of the cotton rope extends into the lamp holder, and the lamp holder is screwed and matched, so that the lamp holder can be screwed on the lamp holder. When the lamp holder is filled with kerosene, the cotton rope sucks the kerosene to the end of the rope.

As long as you light the rope end with a match and cover the lamp tube, you can complete the lighting action. At present, old kerosene lamps are almost extinct.

Electric light, the exact professional name is incandescent light bulb. General term for artificial light source. It is a kind of lamp that emits light by heating the filament to incandescent state by current. The shell of the bulb is made of glass, which keeps the filament in vacuum or low-pressure inert gas to prevent the filament from oxidation at high temperature. Only 7-8% of its electric energy is converted into visible light, and more than 90% of its electric energy is converted into heat energy. Incandescent lamps have low luminous efficiency, however, they are pioneers in the electric light world. The life of modern incandescent lamps is generally about 1000 hours. Electric lamps are made according to the principle that electricity generates heat. At present, tungsten filament is generally used as the filament of light bulb.

[Edit this paragraph] Working principle

An electric lamp is a device that converts electric energy into light energy to provide lighting. Its working principle is: when the current passes through the filament (tungsten filament, the melting point is above 3000℃), heat is generated, and the spiral filament continuously accumulates heat, so that the temperature of the filament reaches above 2000℃. When the filament is incandescent, it will glow, just as red-hot iron can glow. The higher the temperature of the filament, the brighter the light it emits. So it's called incandescent lamp.

From the point of view of energy conversion, when an electric lamp emits light, a lot of electric energy will be converted into heat energy, and only a small part can be converted into useful light energy.

The light emitted by electric lamps is full color light, but the proportion of each color light is determined by the luminescent substance (tungsten) and temperature. The imbalance of proportion leads to the color deviation of light, so the color of the object is not true enough under incandescent lamp. (i.e. low color rendering)

The reason why electric lights will turn black when used for a long time

The tungsten wire that glows in the electric lamp can remain stable at extremely high temperature, and it will not melt, but sublimate directly into gas. When the lights are turned off, the temperature drops, and the tungsten gas condenses into a solid again, covering the inner wall of the bulb. Because tungsten is a black solid, incandescent lamps will turn black after long use.

Electric lamps have a long life. Generally, after blackening, their life will not be long. Black light bulbs will affect the lighting quality and are unsightly. Therefore, it is best to replace it as soon as possible, especially in conspicuous places, which need good lighting to avoid the sudden failure of light bulbs without spare bulbs, which will affect normal lighting's life and cause various inconveniences.

The life of the lamp is related to the temperature of the filament, because the higher the temperature, the easier it is for the filament to sublimate (tungsten directly becomes tungsten gas). Tungsten wire sublimates and becomes thinner, and it is easy to burn out after being electrified, thus ending the life of the lamp. Therefore, the greater the power (wattage) of an electric lamp, the shorter its life.