2004-03-29 日記



29.jpg

今天來談談友人改造電腦power的計畫.因為power的風扇太吵了.所以打算改成可調速的方式.本來打算用串接可變電阻的方式,零件也買好了.小宗宗測試也沒啥問題.後來經高人指點才發現問題可大了,因為一般市面上的可變電阻VR攻率都不大,稍微計算一下發現VR要承受2w以上的功率.一般的VR沒法承受這麼大的瓦數.只好另外想辦法啦~後來msn上多方討論詢問後.發現有顆LM317 IC可以調整電壓,電流可以到0.5A以上,DL到datasheet後,裡面也有現成的應用電路圖可以看.非常完美.傳給友人看過後.就等他的實驗結果啦^^

My friend want to reform his power supply for PC because the fan is very noisy.He try to DIY a small circuit to adject the fan speed and makes it silence.We decide to use VR to do this,but someone told that the current is too high and the VR will be burned-out.Then I thought that there’s an IC called LM317 can help it.LM317 is a IC that can adjust the output volts and we can change the volts to control the fan speed.This looks better than use the VR.I think it will work.