No simple way electrolytic capacitor
As a function of civilian goods for goods, cost, reliability, proposed a more stringent requirement. On the one hand demand for LED light power continues to progress, the price continues to drop. On the other hand, with regard to LED constant current driver source also made a number of demands. In most people's minds inside, LED life expectancy itself is already very high, but the number of life practice is very low, often due to low supply caused by life expectancy. The life expectancy life often depends on the number of power supply electrolytic capacitors. Because life is generally believed that the number of electrolytic capacitors is very low. Assuming a constant current source foundation, there is no electrolytic capacitors, its life will surely be able to count high. Remove the electrolytic capacitors in the future, not to mention the power factor it can be improved. So there are numerous non-electrolytic capacitor current source to attract many people's attention.
First, the non-electrolytic capacitors simple way
Remove the electrolytic capacitor is very simple to do, and it is also capable of the job.
But the life expectancy of this circuit is shorter, because it does not approach the constant current selection so when the input voltage or temperature rises, the current will rise quickly, resulting soon burned LED. Plus limiting resistor can handle despite some doubts, but just 52 percent of its power -73%. Is completely unbearable.
It is necessary to be constant, even the most simple constant current diode.
But this circuit is unable job. Since the input is a half sine wave, LED can not be launched at a low voltage, although the voltage rises to a certain extent, it can be constant, the current waveform at this time near to a rectangular wave, so it can not cause the power factor satisfaction, because only when the current and voltage waveforms are the same, the power factor is equal to 1 competence. It can not be opened to announce A circuit makes it possible to get close to the best current waveform voltage waveform it?
