LED Tube lights are now commonly used to save energy. These are of different types ranging from 12 Watts to 100 Watts. The LED tube light has an LED panel powered by 12 volt LED Drivers. Each section of the panel consists of three 0.5 W White LED chip serially connected with a 20 Ohms (SMD No.200 ) current limiting resistor. Depending on the power output (Watts), the number of 3 LED sections increase. For example, in an 18 W LED Tube light, there will be 36 Chip LEDs (36 / 0.5 W = 18W). In 100 W LED Light, there will be two hundred 0.5 W LED chips. Two or more LED drivers are used to drive the LEDs. Sometimes the LED Tube light fails to light completely. The main reason is the failure of one or more LED driver. Let us see how to repair an LED Tube light.
SMD resistors are small rectangular shaped components with metalized areas at the ends. The metalized areas are used for soldering with the PCB. The SMD resistor has ceramic substrate on to it a metal oxide film is deposited. The thickness and length of this metal oxide film determines the value of resistance. The use of Metal oxide gives good stability and tolerance to the SMD resistors.Unlike color coded resistors, SMD resistors do not have any color bands instead they have numbers printed on it. It is difficult to identify the SMD resistor if the coding method is not known. Here describes the methods to identify the SMD Resistor.