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各位大哥!我一直看不懂这里~.想问一下电路上用红方框画着里面各个元器件的作用?谢谢了 500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/58/2128421192260626.gif');}" onmousewheel="return imgzoom(this);">
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