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/22/1098888156.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">菜鸟提问三极管:汗颜
我打算做一个小功率电源,输入是6.5V的,通过LDO 输出有5V 3.3V.其中5V我想用三极管来控制开断.这样可以防止反串电,相当于二极管来用.三极管的压降应该比较小.可是我做了一个极其简单的.不知道可不可以.三极管:2N2907(PNP) C极输入:5V B极:接1K电阻到地.E极输出5V.可是我负载用10欧姆电阻箱.输出功率很小啊.是怎么回事呢.是我做的不对还是???请大家帮忙啊.感激中.如果可以回复:fengdb@paxsz.com 谢谢大家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/22/1098888156.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">
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