LED multi-layer Electronic Sirens and Speakers basic knowledge
1: An LED multi-layer Electronic Sirens and Speakers, including a dozen or even more LED chips, they are usually connected together. The luminous brightness of each chip is determined by the magnitude of the current passing through it. As a result of the series connection, each LED chip within the LED will automatically through the same current, but the voltage on each chip is different. The forward voltage drop of the LED is typically 3.4V, but varies between 2.8V and 4.2V. LED can be classified to limit the voltage fluctuation range, but this will increase the cost, and the forward voltage drop will still change with the temperature and the use of time. To provide consistent light output, the LED must be driven by a strictly regulated high-efficiency constant current. As an alternative to incandescent LED lights, the power supply must be integrated in the lamp housing.
2: Typical integrated LED Electronic Sirens and Speakers includes drive circuit, LED cluster and can also provide the driver and LED chip for mechanical protection and cooling of the shell.
3: LED driver requirements are very strict. It must be energy efficient and must meet stringent EMI and power factor specifications and can safely withstand various fault conditions. One of the most difficult requirements is to have a dimming function. Due to the inconsistency between the characteristics of the LED lamp and the dimming controller designed for incandescent lamps, it is likely to result in poor performance. The problem may be that the startup speed is slow, blinking, Electronic Sirens and Speakers uneven illumination, or blinking when the brightness is adjusted. In addition, there are inconsistencies in the performance of each unit and LED lights issued audible noise and other issues. These negative conditions are usually caused by false triggering or premature shutdown of the controller and improper control of LED current and other factors.
4: At present, LED products claim to have a greater gap with the actual service life. In the case of limited accumulation of drive circuit design technology, with the assessment of product life to measure the actual life of the method, likely to cause errors. While the stability of the drive line will directly affect the overall stability of the product.