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/84/2944151261537584.gif');}" onmousewheel="return imgzoom(this);">功放开关电源随放大信号频率变化,变压器也发出相应的叫声
用FSCQ1565做的开关电源,带功放测试.功放输入信号为正弦信号,频率从200-20kHz,变压器也随输入信号频率升高而叫声频率也升高,到20KHz时候,变压器几乎没叫声.电源在纯电阻的负载条件下测试,未发现叫声.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/84/2944151261537584.gif');}" onmousewheel="return imgzoom(this);">
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/84/2944151261537584.gif');}" onmousewheel="return imgzoom(this);">