電腦電源的組成部分

1、濾波器

一個電(dian)(dian)(dian)(dian)(dian)(dian)源通常(chang)包含(han)不止一個電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)濾波器，第一個位(wei)于市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)接(jie)入電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)位(wei)置，可以在(zai)一個電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)220V市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)接(jie)口背后發(fa)現它(ta)。其電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)主(zhu)要作用(yong)是(shi)濾除外界(jie)的(de)(de)(de)突發(fa)脈沖和(he)高頻干擾，另(ling)一方(fang)面也會(hui)減少開關電(dian)(dian)(dian)(dian)(dian)(dian)源本身對外界(jie)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁(ci)(ci)干擾。它(ta)的(de)(de)(de)結構雖然簡(jian)單，大(da)都由X電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)、Y電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)和(he)變(bian)壓器型電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)組成(cheng)，但卻是(shi)電(dian)(dian)(dian)(dian)(dian)(dian)源中的(de)(de)(de)重要設備，如(ru)果在(zai)這(zhe)上面偷工減料(liao)的(de)(de)(de)話，電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)屏蔽性能將大(da)打折扣(kou)。如(ru)果拿優質名(ming)牌(pai)電(dian)(dian)(dian)(dian)(dian)(dian)源和(he)普通雜牌(pai)電(dian)(dian)(dian)(dian)(dian)(dian)源比較的(de)(de)(de)話，會(hui)發(fa)現大(da)部分(fen)(fen)雜牌(pai)電(dian)(dian)(dian)(dian)(dian)(dian)源都缺少EMI電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，電(dian)(dian)(dian)(dian)(dian)(dian)源直接(jie)從(cong)市(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)引入PCB。而這(zhe)一點也就成(cheng)為區(qu)分(fen)(fen)電(dian)(dian)(dian)(dian)(dian)(dian)源質量優秀(xiu)與否的(de)(de)(de)核心之一了(le)。

此(ci)外，很多品牌(pai)優質電(dian)(dian)(dian)源(yuan)為(wei)保證輸(shu)入(ru)到(dao)整流(liu)電(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)流(liu)的(de)純(chun)凈，還都設計了第(di)二道(dao)濾(lv)波電(dian)(dian)(dian)路。此(ci)濾(lv)波電(dian)(dian)(dian)路同(tong)樣也是由X電(dian)(dian)(dian)容(rong)、Y電(dian)(dian)(dian)容(rong)和變(bian)壓器型電(dian)(dian)(dian)感組成(cheng)，位置位于PCB上(shang)，靠(kao)近(jin)第(di)一道(dao)EMI電(dian)(dian)(dian)路附(fu)近(jin)。

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2、保護器--壓敏電阻

壓(ya)敏(min)電(dian)(dian)阻是每個(ge)電(dian)(dian)源必不可少的(de)元件，散布在印刷電(dian)(dian)路板（PCB）上(shang)，其作用是對(dui)電(dian)(dian)源提(ti)供(gong)保護。它的(de)原理(li)基(ji)本和家里的(de)保險絲類似，使用自我熔斷方式切斷電(dian)(dian)流。

3、濾波電路

稍微(wei)學(xue)過一(yi)(yi)點電(dian)(dian)子電(dian)(dian)路的(de)人都知道：交流(liu)(liu)(liu)(liu)轉（脈(mo)沖）直流(liu)(liu)(liu)(liu)必須經過一(yi)(yi)個整(zheng)(zheng)流(liu)(liu)(liu)(liu)濾(lv)波電(dian)(dian)路。最(zui)常(chang)見(jian)(jian)的(de)就(jiu)是(shi)由四(si)個二極(ji)(ji)管和兩個濾(lv)波電(dian)(dian)容(rong)組成的(de)橋式濾(lv)波電(dian)(dian)路。計算(suan)機電(dian)(dian)源通常(chang)都采用這種方式整(zheng)(zheng)流(liu)(liu)(liu)(liu)。根(gen)據(ju)封裝(zhuang)模式不同，計算(suan)機電(dian)(dian)源中常(chang)見(jian)(jian)的(de)整(zheng)(zheng)流(liu)(liu)(liu)(liu)濾(lv)波電(dian)(dian)路常(chang)見(jian)(jian)的(de)有(you)兩種：一(yi)(yi)種是(shi)獨立四(si)個二極(ji)(ji)管組成，另外一(yi)(yi)種將四(si)個二極(ji)(ji)管封裝(zhuang)在一(yi)(yi)起，稱為“全(quan)橋”。無論全(quan)橋還(huan)是(shi)獨立二極(ji)(ji)管，所(suo)能承受(shou)的(de)最(zui)低耐(nai)壓(ya)和最(zui)大(da)電(dian)(dian)流(liu)(liu)(liu)(liu)都是(shi)有(you)限制的(de)：耐(nai)壓(ya)應不低于700V，最(zui)大(da)電(dian)(dian)流(liu)(liu)(liu)(liu)應不小于1A。

4、變壓器

在電源(yuan)中(zhong)，變壓(ya)器(qi)是將高壓(ya)轉(zhuan)換(huan)為低(di)壓(ya)，供電腦使(shi)用(yong)。根(gen)據電磁學原理，變壓(ya)器(qi)的轉(zhuan)換(huan)比率(lv)主要(yao)由其線圈的匝數決定(ding)，因此個頭越大(da)的開關型變壓(ya)器(qi)往往可(ke)以傳(chuan)遞更多的能量，也是分辨優(you)質或低(di)劣電源(yuan)的觀察點之一，一定(ding)程度上，變壓(ya)器(qi)的個頭直接影響電源(yuan)的真正(zheng)輸(shu)出功率(lv)和品質。

開關三極管是電源的中心(xin)樞紐(niu)，它(ta)主要負責將轉換后的高壓(ya)(ya)(ya)直流(liu)輸送(song)到開(kai)關(guan)(guan)變壓(ya)(ya)(ya)器上進行降壓(ya)(ya)(ya)，其耐壓(ya)(ya)(ya)程度不得小于800V，輸出電流(liu)通常不能小于5A。開(kai)關(guan)(guan)三(san)極(ji)管(guan)屬于核心(xin)易損部(bu)件，又是電源的核心(xin)部(bu)分，所以開(kai)關(guan)(guan)三(san)極(ji)管(guan)的質(zhi)(zhi)量和電源本身的品(pin)質(zhi)(zhi)也是息息相(xiang)關(guan)(guan)的。

5、保護電路

電(dian)(dian)源(yuan)內(nei)部的(de)(de)保護(hu)電(dian)(dian)路(lu)監視著(zhu)電(dian)(dian)源(yuan)的(de)(de)一(yi)舉一(yi)動(dong)，是電(dian)(dian)源(yuan)的(de)(de)大腦。它負責啟動(dong)電(dian)(dian)源(yuan)并進(jin)行(xing)電(dian)(dian)壓/電(dian)(dian)流的(de)(de)監控和調整，同時在(zai)出現(xian)短路(lu)、斷路(lu)、過壓、過流、欠壓、欠流等情況的(de)(de)時候(hou)進(jin)行(xing)自動(dong)保護(hu)。劣質(zhi)電(dian)(dian)源(yuan)通(tong)常(chang)會(hui)簡化(hua)這部分電(dian)(dian)路(lu)甚至根本(ben)不設(she)置保護(hu)電(dian)(dian)路(lu)，而(er)這一(yi)切都會(hui)給電(dian)(dian)腦系統帶來諸多隱(yin)患。

根據保(bao)(bao)護(hu)(hu)(hu)電(dian)路(lu)的位置(zhi)和監控的類(lei)型(xing)不同，電(dian)源(yuan)內部的保(bao)(bao)護(hu)(hu)(hu)電(dian)路(lu)又分為輸(shu)入端(duan)(duan)過(guo)(guo)壓保(bao)(bao)護(hu)(hu)(hu)、輸(shu)入端(duan)(duan)過(guo)(guo)流(liu)(liu)保(bao)(bao)護(hu)(hu)(hu)、輸(shu)出端(duan)(duan)過(guo)(guo)壓保(bao)(bao)護(hu)(hu)(hu)和輸(shu)出端(duan)(duan)過(guo)(guo)流(liu)(liu)保(bao)(bao)護(hu)(hu)(hu)四(si)個(ge)類(lei)型(xing)，這也(ye)是大部分優質品牌電(dian)源(yuan)宣傳的“四(si)重保(bao)(bao)護(hu)(hu)(hu)電(dian)路(lu)”的由來。顧名思義，過(guo)(guo)壓/過(guo)(guo)流(liu)(liu)保(bao)(bao)護(hu)(hu)(hu)電(dian)路(lu)也(ye)就(jiu)是監視的輸(shu)入/輸(shu)出電(dian)壓/電(dian)流(liu)(liu)出現(xian)異常時自(zi)動生(sheng)效，從而達(da)到保(bao)(bao)護(hu)(hu)(hu)作用。

此外優質電源通(tong)常(chang)還設(she)置有(you)輸(shu)出(chu)端(duan)短路(lu)保(bao)護(hu)。這是個非常(chang)實用(yong)的功能。

6、電路部分

在國家強制實(shi)施(shi)的(de)(de)3C認證(zheng)中，要求電(dian)源(yuan)(yuan)內部(bu)必須增加(jia)一(yi)(yi)個(ge)功(gong)率因素校正電(dian)路，以減少開(kai)關電(dian)源(yuan)(yuan)對外部(bu)電(dian)網的(de)(de)干擾，這就是(shi)現在電(dian)源(yuan)(yuan)內部(bu)的(de)(de)PFC電(dian)路。所(suo)以最新(xin)通過國家CCC認證(zheng)的(de)(de)電(dian)源(yuan)(yuan)內部(bu)都會出(chu)現一(yi)(yi)個(ge)新(xin)的(de)(de)部(bu)件，PFC電(dian)路。通過本(ben)次(ci)對數十款(kuan)電(dian)源(yuan)(yuan)的(de)(de)拆卸，可以發現常見(jian)PFC電(dian)路其實(shi)就是(shi)一(yi)(yi)個(ge)無(wu)源(yuan)(yuan)電(dian)感，其成本(ben)大約在5-6元人民(min)幣左右，個(ge)頭比開(kai)關變壓(ya)器還要大，樣(yang)子很(hen)像(xiang)開(kai)關變壓(ya)器，同樣(yang)用(yong)黃色膠帶封裝。還有(you)一(yi)(yi)些追求空(kong)間的(de)(de)緊(jin)湊型產品或者(zhe)追求性能表現的(de)(de)電(dian)源(yuan)(yuan)產品會使用(yong)成本(ben)在20-30元的(de)(de)有(you)源(yuan)(yuan)PFC元器件，個(ge)頭小但是(shi)功(gong)率因數可以接近于一(yi)(yi)，效果十分優(you)秀。

7、散熱部分

電腦電源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)轉(zhuan)(zhuan)換(huan)效率(lv)通常在70-80%之間，這就意(yi)味(wei)著20-30%的(de)(de)(de)(de) 能(neng)(neng)量(liang)將轉(zhuan)(zhuan)化(hua)為(wei)熱(re)量(liang)。這些熱(re)量(liang)積聚(ju)在電源(yuan)(yuan)(yuan)(yuan)中不能(neng)(neng)及時散(san)發，會使電源(yuan)(yuan)(yuan)(yuan)局(ju)部(bu)溫度過高，從(cong)(cong)而對電源(yuan)(yuan)(yuan)(yuan)造成不必要(yao)的(de)(de)(de)(de)傷(shang)害。因此任何電源(yuan)(yuan)(yuan)(yuan)內部(bu)都包含有散(san)熱(re)裝置，由(you)此得來的(de)(de)(de)(de)風(feng)扇排 風(feng)量(liang)和(he)(he)噪音指數(shu)(shu)也是電源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)兩個重要(yao)指標。電源(yuan)(yuan)(yuan)(yuan)散(san)熱(re)主要(yao)通過散(san)熱(re)片和(he)(he)功(gong)率(lv)管配合進(jin)行，從(cong)(cong)縫(feng)隙中望進(jin)去，都能(neng)(neng)看(kan)到電源(yuan)(yuan)(yuan)(yuan)內部(bu)有巨大(da)的(de)(de)(de)(de)散(san)熱(re)片，上面的(de)(de)(de)(de)大(da)功(gong)率(lv)管 的(de)(de)(de)(de)性能(neng)(neng)和(he)(he)極限參數(shu)(shu)直接(jie)影響(xiang)到電源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)安全承載功(gong)率(lv)和(he)(he)產品成本，也與(yu)電源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)余量(liang)大(da)小密切相(xiang)關。所以說觀察散(san)熱(re)片和(he)(he)上面的(de)(de)(de)(de)功(gong)率(lv)管也是判斷(duan)一個電源(yuan)(yuan)(yuan)(yuan)好與(yu)壞(huai)的(de)(de)(de)(de)方法。