这种焊接电流指示器采用表面安装元件和软性印制电路板制作而成。表面安装元件由于没有元件引出线而不必在印制电路板上钻孔。因此使用小型表面安装元件就能使指示电路重量轻,体积小。为了使指示电路更加小型化,把软性印制电路板卷在变压器芯子 This welding current indicator using surface mount components and flexible printed circuit board made. Surface Mount Components There is no need to drill holes in the printed circuit board due to the absence of component leads. Therefore, the use of small surface mount components can make the instruction light weight, small size. To make the indicator circuit more compact, the flexible printed circuit board is wound on the transformer core