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/64/135831207906577.gif');}" onmousewheel="return imgzoom(this);">各位高手帮我想个小电路,越简单越好
我用一个3.5Vdc电压给单片机供电,但是我现在要求单片机的输入电压是这样动作的,开时,电压要从0V上升到3.5V,慢一些,在大于100ms时间,然后正常,关闭时,电压要很短时间掉到0V,大概小于210-20ms吧,如下图,大家帮我想想看,能用三极管和电容电阻什么的就能实现就可以.
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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/64/135831207906577.gif');}" onmousewheel="return imgzoom(this);">