The terminal voltage of the PN junction constitutes a certain potential barrier. When the forward bias voltage is applied, the potential barrier drops, and the majority carriers of the P region and the N region diffuse to each other. Since the electron mobility is much larger than the hole mobility, a large number of electrons will diffuse into the P region, which constitutes the injection of minority carriers into the P region. These electrons recombine with holes in the valence band, and the energy obtained during recombination is released in the form of light energy. This is the principle of PN junction light emission.

Features:

1. Voltage: LED lamp beads use low-voltage power supply, and the power supply voltage is between 2-4V, which varies according to different products, so it is a better power supply than high-voltage power supply to drive it, especially suitable for public places;

2. Current: The working current is 0-15mA, and the brightness becomes brighter with the increase of the current;

3. Efficiency: consumes 80% less energy than incandescent lamps with the same luminous efficacy;

4. Applicability: very small, each unit LED chip is 3-5mm square, so it can be prepared into various LED lamp beads;

5. The LED lamp bead shape device is suitable for variable environments; br> 6. Response time: the response time of incandescent lamps is milliseconds, and the response time of LED lamps is nanoseconds;

7. Environmental pollution: no harmful metal mercury;

8. Color: Changing the current can change the color. The light-emitting diode can easily adjust the energy band structure and band gap of the material through chemical modification methods to achieve multi-color emission of red, yellow, green, blue and orange. For example, an LED that is red when the current is small can turn orange, yellow, and finally green as the current increases.