...开关电源改输出电压...

建兴19V3.42A的,想改成12V的,功率尽量和原来差不多,想问如何改?
仅仅是取样电阻给改一下?
图是借用的
实测发现R7是32K多一点,R8是4.9K,均是拆下来测的.取样电路与这个类似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/75/2806241236581501.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">
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