the measurement methods most obvious advantage is that, in the practical application of led, as long as the work of lighting the led junction temperature values near the target, using this method have a good simulation of the parameters, it also measured the parameters of these makes sense, and its light, color, elecical parameters measurement results have good reproducibility. figure 1 led junction temperature measurement and the use of vf-tj junction temperature curve in setting conditions of light, color, elecical parameter measurement system. third, led lighting into the measurement of junction temperature after 1, led lighting into the junction temperature conol and measurement after the need for led lighting when applied to people in general want to have tens of thousands of hours of life, but to measure the use of led lighting apparatus light attenuation and life, in accordance with the requirements of the u.s.
vinyl signs according to equation 2.2 we can see, and d is proportional to the duty cycle d can be changed as long as the change in primary current size, it can change the size of the output power. 2.2 the advantages and disadvantages of theory, this topology is simple, low cost, but careful analysis will find that this approach has many drawbacks. the first is difficult to conol, often large deviations, together with open-loop conol, precision is difficult to ensure, in the volume, use the same power output duty cycle will result in significant bias, is directly reflected in the led lights on the great brightness bias, it is difficult to ensure consistency.
led scrolling signled, 30 led. there are 60cm, 80cm and so on, different users have different specifications. and can be arbiarily cut off the light can not affect any extension. the fpc flexible material can be bent, folded, winding, three-dimensional space can be moved around and setch without breaking. irregular areas for small places and space, but also because any bending and winding can be suitable for any combination of advertising in a variety of decorative motifs. 2, led light bar is made with the pcb board assembly circuit board hardware, led useful for the assembly of smd led, led-line is also useful for assembly, depending on the different needs of different components. light bar has the advantage of easier fixation, processing and installation are relatively easy; disadvantage is not free to bend, not suitable for irregularities. smd led light bar have used 18 led, 24 .
lawn signs
