Q:为何产品规格书表示的输入电压范围是90-305，标签是100-240或者100-277？
Ans:产品输入电压的标定，受产品内部零部件的认证电压范围所限，同时安规测试机构也会根据给定的工作电压范围，加严±10%来测试。
Q:Why led drivers could not use in parallel in series
Ans:When led drivers connect in series or parallel, the led lights may not working. So it could not be used as parallel or series.
Q:LED电源与LED灯具负载不匹配问题？
Ans:LED灯具厂家在选用LED电源时，有发现，点灯初始状态LED整灯功率小于额定值，LED灯具发热后，整灯功率输出逐渐达到额定值，其原因是LED灯珠串联电压大于电源的额定输出电压，电源处于限功率保护模式。
每颗LED灯珠的正向Vf值，在正常热机时的典型值为3V，而冷机时为3.2V，低温可能更高。所以，在匹配LED电源时，应根据项实际LED冷态的最高Vf值来选择合适的电源型号。
Q:What is the safety shell temperature? What is the quality assurance shell temperature?
Ans:The safety shell temperature refers to the maximum working shell temperature when under safety testing and regardless of the lifespan of the product,.
The quality assurance shell temperature is to ensure that the product can be stable and reliable during the warranty period, and the maximum working temperature of the power supply is limited.
Q:What”s the difference between Class2 and ClassII
Ans:Class 2 is from UL 1310(Class 2 power units), mainly referring to the product's output is safe and comply with UL1310 standard requirements; Class 2 must meet the following electrical requirement: 1)DC output voltage<60VDC (Canada<42.4V), and the output dc voltage<30V when using in washy environment. 2) Total power < 100W 3) rated output nominal current<5A (the maximum over load current no more than than 8A) 4) meet the related abnormal test requirements of UL1310.
Class II from IEC standards or equivalent standard, is mainly refers to prevent electric shock insulation product structure or unique insulation type. For the lED power supply, not only rely on basic insulation protection against electric shock, but also includes additional security measures, such as double insulation or reinforced insulation, but there is no protection grounding or depend on the installation conditions, has its own symbol.
