What is the principle of LED string lights?

LED (Light Emitting Diode) is a solid-state semiconductor device, which can directly convert electricity into light. The core of LED is semiconductor chip. The chip is fixed on the bracket, with one end as the negative electrode and the other end connected to the positive electrode of the power supply, so that the whole chip is encapsulated by epoxy resin.

The semiconductor wafer consists of two parts, one is a P-type semiconductor, in which holes are dominant, and the other is an N-type semiconductor, mainly electrons. But when these two semiconductors are connected together, a pn junction is formed between them.

When the current acts on the chip through the wire, the electrons will be pushed to the P region, where they will recombine with holes and then release energy in the form of photons, which is the principle of LED light emission. The wavelength of light, that is, the color of light, is determined by the material forming the pn junction.

LED lamps, driven by alternating current, will flash like ordinary incandescent lamps, and the series voltage will become smaller and the power will decrease, so the brightness will decrease.

Extended data

The biggest advantage of LED lamp is energy saving and environmental protection. The luminous efficiency of light reaches more than 100 lumens/watt, while ordinary incandescent lamps can only reach 40 lumens/watt, and energy-saving lamps hover around 70 lumens/watt.

So with the same wattage, the effect of LED lamps will be much brighter than incandescent lamps and energy-saving lamps. 1 watt LED lamp has the brightness equivalent to an energy-saving lamp of about 2 watts. 5 watt LED lamp 1000 hours consumes 5 degrees of electricity, and the service life can reach 50,000 hours. The LED lamp has no radiation.

Baidu encyclopedia -LED lamp

Baidu encyclopedia -led lighting