The working principle of transistorized welding power supply is to utilize transistor charging and discharging to generate low voltage and high current for resistance welding. Before turning on the power, check whether the external connection cables are loose; whether each signal transmission line is connected properly; whether the electrodes on the left and right of the welding head are parallel; whether the welding surface (electrode) is smooth and flat; whether the air pressure is adjusted to between 0.4~0.5; and whether the cylinder of the welding head is in the reset position (not pressed down). When adjusting the position of the welding head,