led, light source and so on, luminous flux measurement is more difficult, then we should be measured with an integrating sphere. illuminance illuminance illuminance per unit area is accepted by the amount of incident light. in imperial units, the 1 square foot of area received a lumen, defined as 1footcandel. metric units, 1 lumen per square meter to 1 lux (lux), 10.76lux = 1footcandle. of course, the probe can not have such a large area, so the size of the probe must be multiplied by the appropriate multiple.
led sign boardled (light emitting diode) because of its high intensity, low power consumption, long life, high reliability, easy to drive, easy to link up with the ic characteristics, has been widely used in transportation, commercial advertising and instrumentation displays. the impact of a variety of led color display is a key factor that determines the color of led is its wavelength characteristics, due to the relative spectral power distribution of led is a narrow-band quasi-monochromatic light spectrum, so the wavelength measurement of led particularly important.
led message displayspositive led reverse leakage current ir color led light colors at points, can be divided into red, orange, green (and yellow segments, the standard green and pure green), blue and so on. in addition, some light-emitting diode contained in two or three colors of chips. light emitting diode based on doped or not doped at the scattering agent, colored or colorless, the various colors of light-emitting diodes can also be divided into colored transparent, colorless, transparent, colored the number of different led illuminated, then the output level changes. figure 9 is constituted by the five led level meter. when the input signal level is low, and do not have light. input signal level increases, the first light led1, led2 and then increase the light ... .... (v) the resistance to 200kω, reverse resistance value of α. if the forward resistance value of 0 or ∞, reverse resistance is very small or 0, then damaged. this detection method can not actually see the luminous led, because × 10kω block can not。
led message display
