Why do LED bulbs with the same wattage have different brightness?

<p>Why do LED bulbs with the same wattage have different brightness?There are several reasons for this phenomenon:</p><p><br></p><p>1. Different light source efficiency</p><p>LED lamps consume electricity and emit light. This involves the issue of conversion efficiency. The performance form of the light efficiency index is lm / w. This is how many lumens of luminous flux can be converted per electric power. When LED was first born, the light effect was only a few ten lumens per watt. Now good quality LED lamp beads can reach 200 lm / w, a difference of several thousand times. Until now, the light efficiency of LEDs has been continuously refreshed every year. Therefore, it is not surprising that the same specification light bulbs assembled with lamp beads from different periods or from different manufacturers have different brightness.</p><p><br></p><p>2. Different power efficiency</p><p>LED lamp beads are non-linear components with negative temperature thresholds and are extremely sensitive to changes in temperature and voltage. Therefore, whether it is AC or DC power supply can not directly supply LED, but to use constant current drive to work. The efficiency of constant current drive with different masses varies widely, ranging from 50% to 90%. Therefore, even if a high-efficiency light source is selected, such as low efficiency of constant current driving, it will also cause insufficient brightness.</p><p><br></p><p>3. Power labeling based on different</p><p>At present, the power labeling of the LED lamp market is relatively chaotic. Some are based on the actual power consumption of the entire lamp, while others are based on the power of the lamp beads. Because the efficiency of the power supply cannot be 100%, originally the same power LED bulbs may be labeled with different power by different manufacturers.</p><p><br></p><p>4. The area of ​​the light emitting part is different</p><p>Two differently shaped bulbs of the same wattage sometimes look very different in brightness. For example, a small light bulb will look brighter than a large light bulb. The light bulb looks brighter than the lamp etc.</p><p>This is because the area of ​​the light emitting portion is different. Because the same light energy is distributed on different areas, the luminous intensity per unit area is inversely proportional to the area. So although the brightness of the light source itself is different due to the different light emitting areas, the lighting effect is still very close.</p><p><br></p><p>5.Color temperature is different</p><p>Color temperature is an important indicator of lighting fixtures. What is color temperature? In popular terms, it is like a piece of heated iron (actually an idealized black body) that starts to be red, and gradually turns yellow, white, and finally blue as the temperature rises. Therefore, we call reddish light as low color temperature and blued light as high color temperature.</p><p>In this way, "hue" can be expressed by temperature. The unit of color temperature is "K", which is 273.15 different from our commonly used "℃". Both: 0 ° C is equivalent to 273.15K.</p><p>The human eye's ability to perceive different color temperature light is different. Under the premise of the same luminous flux, high color temperature light will look brighter.</p>