1: the use of STM8 industrial microcontroller control . 2: strong and weak through optocoupler isolation, safe operation. 3: the power and the foot switch adopts the screw free fast connection terminal, more convenient and . 4: input time, current using high-precision single potentiometer, to input, convenient 5: on-board power supply, state, foot, trigger indicator, working state clearly visible. The control panel of the spot welding machine is a controller which is independently developed for the DIY or the simple resistance welding. The principle of silicon controlled phase shifting triggering is adopted to adjust the time and the current to achieve the purpose of welding. the design of crossing detection circuit to the phase shift accuracy. the controller is compatible with 100A . digital control interface, you can display the current time and current settings. time input 1-50, unit (1 cycles is 20ms), current input (30-99%) Types:40A Colour:Red Material: ABS Size: 8 x 6 cm Contents: 1 x Main Board 1 x Display Board 1 x Cable Only the above content, other are not included. Note: Light reflection and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.