Incandescent lamp
The filament in an incandescent lamp is a tungsten filament, and its main component is tungsten. When the tungsten wire is energized, because the resistive electric energy of the tungsten wire is converted into internal energy, the tungsten wire is heated and the temperature rises. Generally, metals will emit light after being heated to a certain level (iron is also luminous when heated to red), that is, the internal energy has converted into light energy.
Neon lights
The principle is that a closed glass tube is filled with neon, helium, argon and other gases. Two metal electrodes are installed at both ends of the lamp tube. The electrodes are generally made of copper materials. The electrode leads are connected to the power circuit and equipped with a high-voltage transformer. A voltage of 10-15kV is applied to the electrodes. Since the gas in the tube is composed of countless molecules, the molecules and atoms are neutral under normal conditions. Under the action of high voltage, a small amount of free electrons move to the anode, and the rapid ionization of gas molecules excites the electrons to accelerate their movement, making the gas in the tube conduct electricity and emit colorful glow (also known as rainbow light).
High pressure sodium lamp
It emits a golden white light when used. When the bulb is started, an arc is generated between the electrodes at both ends of the arc tube. Due to the high temperature of the arc, the sodium amalgam in the tube is heated and evaporated into mercury vapor and sodium vapor. During the movement of the electricity emitted by the cathode to the anode, it hits the atoms of the discharge material, which makes it gain energy to generate ionization excitation, and then returns from the excited state to the stable state, or from the ionized state to the excited state, and then returns to the base penta infinite cycle . The excess energy is released in the form of light radiation, which produces light.
Fluorescent light
A fluorescent lamp is a cathode low-pressure mercury vapor discharge lamp. A light source that converts ultraviolet rays generated by discharge into visible light through phosphor powder. The principle of light emission provides pulse voltage for the electronic ballast to preheat the filament and activate the electron emission material on the filament (cathode) to generate electrons. Electrons collide with mercury atoms inside the lamp tube to generate ultraviolet light, and the ultraviolet light refracts visible light through the fluorescent powder coated on the tube wall of the lamp tube.
LED is a solid-state semiconductor device that can convert electrical energy into visible light, and it can directly convert electricity into light. Semiconductor wafer is made up of two parts, and a part is P-type semiconductor, and hole occupies an leading position in it, and the other end is N-type semiconductor, and here mainly is electron. But time these two kinds of semiconductors couple together, between them, just form a P-N junction. When electric current acts on this wafer by wire time, electron will be pushed to P district, and in P district, electron is with hole-recombination, then will send energy with the form of photon.
