This control panel of the spot welding machine is independently developed for the DIY or the simple resistance welding. The principle of silicone controlled phase shifting triggering is adopted to adjust the time and the current to achieve the purpose of welding. Equipped with digital display, you can see the time and current directly, simple and easy to use. Strong and weak is isolated by optocoupler, to operate. Using high precisions single bit potentiometer, to and convenient input. A -crossing detection circuit to the phase . Specifications: Name: Spot Welding Tool Set Type: 9V 40A Voltage: AC220V Colour: Red Material: metal, plastic Contents: 1 set x Spot welding machine control board Only the above content, other are not included. Note: Light 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.