 Wysłany: Wto 4:05, 12 Kwi 2011 Temat postu: LED thermal conductivity and thermal silica film G |
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| AR lamps may be more than the actual power of 9W or less than 9W,display boards, directly reflected in the maximum brightness of the lamp is rated or not to be brighter than the rating. When the PAR lamp when the actual power of less than 9W,LED open sign, and drive the output power is still 9W, then the current flowing through the LED has been over rated, long-term work on the LED's life and color will have a certain effect. In addition, even if there is no bias LED factory, as shown in Figure 1.2, with temperature and working time change,
when the change makes the LED's rated power is less than 9W, the long-term work will affect the use of LED life and color. Again, the power of compatibility issues. The constant power control mode are pre-configured output power, when the received light power and pre-set does not match the power, LED lights do not work. When the connection of the lamp power is less than the default power,business signs, or even burned LED lights. There is a problem of no-load loss, due to constant power control scheme of the output power only with the input voltage and the size of the conduction angle, and then when there is no LED lights, still have the corresponding power output, making the no-load loss change very large. Finally,restaurant board, dimmer compatibility issues. Because LED is used to replace incandescent lamps before, so also must be dimming LED SCR dimming. Incandescent lamp is a pure resistive load, the conduction of the SCR will not be affected, but the LED driver circuit formed by the switching power supply, it is not a pure load, so the SCR would have been affected. SCR chopper can easily lead to distortion of the waveform, in particular, is difficult to maintain a good on-state. |
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