Why do fluorescent lamps need a ballast to limit current
The fluorescent lamp emits light because there is mercury vapor and a small amount of inert gas inside the tube, and there are phosphors on the tube wall. Therefore, when the fluorescent lamp is ignited, a high voltage is required to stimulate the movement of the mercury vapor particles to produce white light. When the filament is ignited and glows normally, only a small current is allowed to pass. At this time, the voltage applied to the lamp tube is required to be lower than the power supply voltage.
The function of the ballast is the component that limits the current and generates instantaneous high voltage on the fluorescent lamp. It is made by winding enameled wire on the laminated silicon steel sheet iron core. In this way, the coil with the iron core will be It will self-induct and generate high voltage, which is added to the filaments at both ends of the fluorescent tube to light up the tube.
Nowadays, there are fewer and fewer fluorescent lamps using ballasts, because fluorescent lamps have many shortcomings. First, the fluorescent light has stroboscopic light, which is harmful to the eyes. Second, the fluorescent tube has a short lifespan, and the two ends will turn black after a short period of time, and finally cannot be ignited. The third is that there is buzzing oscillating noise and radio wave radiation when the ballast is working, which obviously interferes with the mid-band of the radio. Because of various shortcomings, LED light panels are now commonly used in homes.
The damage of the fluorescent lamp rectifier is usually caused by the damp or aging of the coil insulation paint. In principle, the coil can be re-wound, but it is very troublesome, and it is best to replace it with a new one. You can also change the electronic ballast, there is no noise and the light is soft. You can also use the LED tube directly without the ballast, remove the original broken ballast, or disconnect the two wires, short-circuit them, and wrap them. There is also a kind of LED light that has zero live wire at both ends. Just remove the starter. If you don’t know how to make it, find someone who knows a little bit of electricity and you’ll understand.
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