Why do led chips need series resistance? It is derived from better protection of LED lamp beads.
What does that mean? It is because the LED has a working voltage limit. If the working voltage exceeds the working voltage, the forward PN junction current is too large, which is easy to burn the LED. Therefore, a resistor in series is required to protect the LED.
In the early days, in 1962, LED lamp beads could only emit red light with low luminosity, and then other monochromatic lights were developed. Today, LED lamp beads can emit light including visible light, infrared light and ultraviolet light, and the luminosity has also increased to high brightness or even super brightness. . The LED lamp beads were initially used as indicator lights, display panels, general lighting, medical devices, etc.
The LED lamp bead is essentially a light-emitting device, which emits energy through the recombination of electrons and holes, and efficiently converts electrical energy into light energy. However, because the LED lamp bead has a working voltage limit, exceeding the working voltage, the forward PN junction If the current is too large, it is easy to burn the LED lamp beads, so a resistor needs to be connected in series.
Why? Because of:
1. The led lamp bead is added with resistance in order to reduce the working current.
2. The LED lamp beads do not have to be added with resistors. If the power supply is constant current, no resistors are required. However, because LED nonlinear components are very sensitive to power and voltage, they cannot be controlled in voltage mode. The brightness of LED lamp beads is mainly controlled by current. The purpose of adding resistance is to limit the current. In fact, adding resistance will affect the conversion efficiency of LED lamp beads. The low-power LED lamp beads can ignore the loss on the resistance, while the high-power LED lamp beads are generally powered directly by a constant current power supply.
3. The LED lamp bead is added with a resistor. In the final analysis, it is because if the resistor is not added, the LED lamp will cause serious heating of the PN junction due to the excessive operating current and burn out the PN junction. Too high voltage will obviously lead to too high current, and light decay will also increase. Shorten the life of LED lamp beads.
Speaking of which, do you understand why the LED lamp beads need to be added with resistors?
