LCD Welding Filter

First,The welding filter using the liquid crystal light valve is called LCD Welding Filter, referred to as ADF; Its working process is: the arc signal when soldering the arc is converted into a micro-ampere current signal by the photosensitive absorber tube, converted from the sampling resistor into a voltage signal, coupled by capacitance, removes the DC component in the arc, and then amplifies the voltage signal through the operation amplification circuit, and the amplified signal is selected by the dual T network, and sent to the switch control circuit by the low-pass filter circuit to issue a driving command to the LCD driver circuit. The LCD drive circuit changes the light valve from the bright state to the dark state, so as to avoid the damage of the arc light to the welder’s eye. The voltage of up to 48V makes the liquid crystal instantly black, and then shuts down the high voltage in a very short period of time, so as to avoid the high voltage being continuously applied to the liquid crystal, damaging the liquid crystal chip, and increasing power consumption. The DC voltage in the liquid crystal drive circuit, whose output is proportional to the duty cycle, drives the liquid crystal light valve to work.