Different magnetic materials will have different magnetic permeability and temperature characteristics. Among them, temperature characteristics are the most important, because in the operation of an energy-saving lamp, the magnetic ring must go through normal temperature, high temperature (up to 100 ℃), low temperature, and then work continuously in high temperature. However, the temperature curves of different materials can vary greatly, with those with low magnetic permeability appearing flatter in the front half and those with higher magnetic permeability appearing steeper; At different temperatures, the variation of saturated magnetic induction intensity BS will also be different. Assuming that the BS value of 3K material is 200 at room temperature, but it will rise to 300 at 100 ℃. Similarly, the BS value of 2.5K material is 200 at room temperature, but it is only 250 at 100 ℃. Changes in temperature can cause variations in BS values u, H, and HC; Changes in BS values can cause changes in the working status of energy-saving lamp circuits; An increase in BS value will cause a decrease in the driving current obtained by the transistor. Therefore, in a 110V line, if a magnetic ring with a relatively large change in BS value at high temperatures is selected, it will cause the lamp to turn off and then turn on immediately at high temperatures, and the lamp will not start; The filaments at both ends of the lamp tube turn red because the lamp tube cannot be started; The power will be twice the rated power. Due to the malfunction of the lamp tube, the temperature of the two ends of the filament will rise very high (nearly 300 ℃ or above), which will burn off the plastic parts. If a magnetic ring with a BS value that does not change significantly with temperature, i.e. a magnetic ring with low magnetic permeability, is selected, the above problem can be solved. But there is another issue to consider when it comes to the high and low magnetic permeability: its loss. Generally, magnetic rings with high permeability, such as 5K and 10K, have very small losses. After being made into a finished pulse transformer, due to their relatively small magnetic circuit impedance and delay time, their output waveform can be made very well, but they are unable to adapt to the temperature problems mentioned above; When using a lower magnetic permeability, although its surface performance is not as good as 5K and 10K, it will not experience the phenomenon of the light not starting when starting. Jiangmen powder 2.5K magnetic ring is suitable for making 110V directly driven lamps; Zhitong Electronics 3K magnetic ring is suitable for 220V lamps. Why? The reason is that the 110V direct drive circuit is prone to causing thermal start-up problems; And there is no hot start issue with the 220V circuit. The magnetic ring of Jiangmen powder has little interference with temperature, while the 220V energy-saving lamp needs to reduce the power appropriately at high temperatures, so the driving current of the transistor needs to be reduced appropriately to avoid the lamp burning out at high temperatures and high voltages. Assuming the temperature rises, the amplification factor of the transistor increases, the current increases, and the lamp power increases. At this point, it is necessary to adjust the power appropriately by using a Zhitong 3K magnetic ring, which is sensitive to temperature rise. When the temperature rises, BS increases accordingly, the driving current of the transistor decreases, and the lamp power decreases, ensuring the contradiction between temperature rise and lamp power.