Now the LCD TV has entered the maintenance period. In order to keep up with the trend of the times, our maintenance personnel should master the knowledge of LCD as soon as possible. Now I will introduce the knowledge about the LCD TV tube. The LCD TV is passive and needs the tube to light up the entire LCD. Therefore, it is important to understand the knowledge of the lamp. In actual maintenance, the incidence of LCD TV backlight circuit is very high.
The backlight tubes of LCD TVs can be divided into CCFL tubes or cold cathode tubes. EEFL has no cold cathode lamps, and a new product, LED light-emitting diodes, is a light source arranged in a matrix of white light-emitting diodes. Currently, only Hisense has such advanced light sources.
The difference between CCFL and EEFL in luminescence: CCFL's electrode is inside the tube, EEFL's electrode is outside the tube, the brightness of EEFL tube is more than 60% higher than that of CCFL.
The driving difference between EEFL and CCFL: CCFL can only be driven by a single lamp, because the voltage and current characteristics of each lamp are different, driving all the lamps with the same waveform to emit light will cause the overall brightness of the LCD screen to be uneven. EEFL can be driven in parallel, pay attention when replacing the lamp.
The difference between EEFL and CCFL in terms of circuit appearance: CCFL requires multiple transformers to drive multiple lamps, that is, one transformer drives one lamp, while EEFL only needs one transformer or the secondary of two transformers to drive and light all parallel lamps tube. In this way, from the appearance of the inverter board, we can identify what kind of lamp the LCD TV is.click here