means surface mounted light emitting diode. SMD patch is helpful to improve production efficiency and application of different facilities. It is a solid semiconductor device that can directly convert electricity into light with a voltage from 1.9 to 3.2 and the red and yellow light requires the lowest voltage. The heart of the LED is a semiconductor chip. One end of the chip is attached to a bracket, which is a negative electrode, and the other end is connected to the positive electrode of the power supply, so that the whole chip is encapsulated by epoxy resin. A semiconductor chip consists of two parts, one is a P - type semiconductor in which holes predominate, and the other is an N - type semiconductor in which electrons predominate. However, when the two semiconductors are connected, a P-N junction is formed between them. When a current is applied to the chip through a wire, electrons will be pushed to the P region, where they recombine with holes and then emit energy in the form of photons. This is the principle of LED luminescence. The wavelength of light, that is, the color of light, is determined by the material forming the P-N junction.
LED is light emitting diode in English. LED is the abbreviation of light emitting diode, which is a popular name.
1. Voltage: LED uses a low voltage power supply of 2-4V, which varies according to different products. So it is a safer power supply than that uses higher voltage, especially suitable for public places;
2. Current: the working current is 0 - 15mA, and the brightness varies with the increase of current.
3. Efficiency: Energy consumption is 80 % less than incandescent lamps with the same luminous efficiency.
4. Applicability: It is very small, each unit LED chip is 3-5mm square, so devices of various shapes can be prepared and are suitable for variable environments.
5. Stability: 100,000 hours, light attenuation is 50 % of the initial value.
6. Response Time: The response time of its incandescent lamp is on the order of milliseconds, but the response time of its LED lamp is on the order of nanoseconds.