一、電解電容和普通電容簡介

一般來說有極性電容指的都是電解電容一類的電容，雖然確實(shi)存(cun)在(zai)著無極(ji)(ji)性電(dian)(dian)解(jie)電(dian)(dian)容(rong)，但(dan)在(zai)市(shi)面上不太常(chang)見(jian)，而(er)且價格也比較貴。常(chang)見(jian)的(de)電(dian)(dian)解(jie)電(dian)(dian)容(rong)都是(shi)由(you)陽極(ji)(ji)鋁箔和陰極(ji)(ji)的(de)電(dian)(dian)解(jie)溶液分別形成(cheng)兩(liang)個電(dian)(dian)極(ji)(ji)，由(you)陽極(ji)(ji)鋁箔上產生的(de)一層氧化鋁膜做為電(dian)(dian)介(jie)質的(de)電(dian)(dian)容(rong)，電(dian)(dian)解(jie)電(dian)(dian)容(rong)在(zai)電(dian)(dian)路中也必(bi)須注意極(ji)(ji)性。

普通的(de)電(dian)(dian)容(rong)(rong)(rong)是(shi)大部分是(shi)無極(ji)(ji)(ji)性(xing)的(de)，也可以把(ba)兩個電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)陽極(ji)(ji)(ji)或陰極(ji)(ji)(ji)相對串連(lian)形成(cheng)無極(ji)(ji)(ji)性(xing)電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)。一般(ban)來說，低于(yu)1μF的(de)低值電(dian)(dian)容(rong)(rong)(rong)大多數是(shi)無極(ji)(ji)(ji)性(xing)之分的(de)，但是(shi)具有(you)1μF或更大電(dian)(dian)容(rong)(rong)(rong)值的(de)電(dian)(dian)容(rong)(rong)(rong)幾乎都是(shi)有(you)正負極(ji)(ji)(ji)之分的(de)。至今為止(zhi)，常用有(you)極(ji)(ji)(ji)性(xing)電(dian)(dian)容(rong)(rong)(rong)是(shi)電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)，有(you)極(ji)(ji)(ji)性(xing)電(dian)(dian)容(rong)(rong)(rong)的(de)正引(yin)線(xian)總會長一些，即使是(shi)標(biao)志(zhi)磨損或者被完(wan)全抹去，我們也能夠辨認出極(ji)(ji)(ji)性(xing)。

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二、電解電容和普通電容的區別

1、介質不同

有(you)極(ji)(ji)性(xing)(xing)電容(rong)(rong)大(da)多(duo)(duo)采(cai)用(yong)電解質(zhi)(zhi)(zhi)(zhi)做介質(zhi)(zhi)(zhi)(zhi)材料(liao)，通常同(tong)體積的(de)電容(rong)(rong)有(you)極(ji)(ji)性(xing)(xing)電容(rong)(rong)容(rong)(rong)量大(da)。另(ling)外，不(bu)(bu)同(tong)的(de)電解質(zhi)(zhi)(zhi)(zhi)材料(liao)和(he)工藝制造出的(de)有(you)極(ji)(ji)性(xing)(xing)電容(rong)(rong)同(tong)體積的(de)容(rong)(rong)量也(ye)會不(bu)(bu)同(tong)。再有(you)就是耐(nai)壓和(he)使(shi)用(yong)介質(zhi)(zhi)(zhi)(zhi)材料(liao)也(ye)有(you)密切關系。無(wu)極(ji)(ji)性(xing)(xing)電容(rong)(rong)介質(zhi)(zhi)(zhi)(zhi)材料(liao)也(ye)很多(duo)(duo)，大(da)多(duo)(duo)采(cai)用(yong)金屬(shu)氧(yang)化膜、滌綸等(deng)。由于介質(zhi)(zhi)(zhi)(zhi)的(de)可(ke)逆(ni)或不(bu)(bu)可(ke)逆(ni)性(xing)(xing)能(neng)決(jue)定了(le)有(you)極(ji)(ji)、無(wu)極(ji)(ji)性(xing)(xing)電容(rong)(rong)的(de)使(shi)用(yong)環境。

2、性能不同

性(xing)(xing)能(neng)就是使用(yong)(yong)(yong)的(de)要(yao)求，需求最大(da)化就是使用(yong)(yong)(yong)的(de)要(yao)求。如(ru)果在(zai)電(dian)(dian)視機里(li)電(dian)(dian)源(yuan)部(bu)分用(yong)(yong)(yong)金屬氧化膜電(dian)(dian)容(rong)器(qi)做濾波的(de)話，而且要(yao)達(da)到濾波要(yao)求的(de)電(dian)(dian)容(rong)器(qi)容(rong)量(liang)和耐壓。機殼內(nei)恐怕(pa)也(ye)就只(zhi)能(neng)裝(zhuang)個(ge)電(dian)(dian)源(yuan)了。所以(yi)(yi)作為濾波只(zhi)能(neng)使用(yong)(yong)(yong)有(you)極性(xing)(xing)電(dian)(dian)容(rong)，有(you)極性(xing)(xing)電(dian)(dian)容(rong)是不可(ke)逆的(de)。就是說(shuo)正極必須接(jie)高電(dian)(dian)位端(duan)，負極必須接(jie)低電(dian)(dian)位端(duan)。一般電(dian)(dian)解電(dian)(dian)容(rong)在(zai)1微(wei)法(fa)拉以(yi)(yi)上(shang)，做偶(ou)合(he)、退偶(ou)合(he)、電(dian)(dian)源(yuan)濾波等。無極性(xing)(xing)電(dian)(dian)容(rong)大(da)多在(zai)1微(wei)法(fa)拉以(yi)(yi)下，參與諧振、偶(ou)合(he)、選頻、限流、等。當然也(ye)有(you)大(da)容(rong)量(liang)高耐壓的(de)，多用(yong)(yong)(yong)在(zai)電(dian)(dian)力(li)的(de)無功(gong)補償(chang)、電(dian)(dian)機的(de)移(yi)相、變(bian)頻電(dian)(dian)源(yuan)移(yi)相等用(yong)(yong)(yong)途上(shang)。

3、容量不同

電解(jie)電容的容量要(yao)比(bi)普(pu)通電容大。

4、結構不同

原則(ze)上講不(bu)考慮尖端放電(dian)(dian)的(de)情況下，使用環境需要什么形(xing)(xing)(xing)(xing)狀(zhuang)的(de)電(dian)(dian)容(rong)(rong)都可以。通常用的(de)電(dian)(dian)解電(dian)(dian)容(rong)(rong)（有極性(xing)電(dian)(dian)容(rong)(rong)）是(shi)圓(yuan)(yuan)形(xing)(xing)(xing)(xing)，方型(xing)用的(de)很少。無極性(xing)電(dian)(dian)容(rong)(rong)形(xing)(xing)(xing)(xing)狀(zhuang)千奇(qi)百變。像管型(xing)、變形(xing)(xing)(xing)(xing)長方形(xing)(xing)(xing)(xing)、片型(xing)、方型(xing)、圓(yuan)(yuan)型(xing)、組(zu)合方型(xing)及圓(yuan)(yuan)型(xing)等等。當然還有無形(xing)(xing)(xing)(xing)的(de)，這里無形(xing)(xing)(xing)(xing)指(zhi)的(de)就是(shi)分布電(dian)(dian)容(rong)(rong)。對于分布電(dian)(dian)容(rong)(rong)在高頻和中頻器件中決(jue)不(bu)可忽(hu)視。

三、無極性電容可以代替有極性電容嗎

理想的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，本來是(shi)沒有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)。但是(shi)在實(shi)際(ji)中，為(wei)了(le)獲得大容(rong)(rong)(rong)(rong)量，就(jiu)(jiu)(jiu)使(shi)用(yong)了(le)某些特殊的(de)材(cai)料和(he)結構，這(zhe)就(jiu)(jiu)(jiu)導(dao)致了(le)實(shi)際(ji)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)有(you)(you)(you)些是(shi)有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)。常(chang)見的(de)有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)有(you)(you)(you)鋁電(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，鉭電(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)等。電(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)一(yi)般是(shi)容(rong)(rong)(rong)(rong)量相對比較大的(de)。如果要(yao)做一(yi)個(ge)大容(rong)(rong)(rong)(rong)量的(de)無極(ji)(ji)性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，就(jiu)(jiu)(jiu)沒那么容(rong)(rong)(rong)(rong)易(yi)了(le)，體積(ji)會變得很(hen)大。這(zhe)就(jiu)(jiu)(jiu)是(shi)為(wei)什么在實(shi)際(ji)的(de)電(dian)(dian)(dian)(dian)(dian)路中，為(wei)什么會有(you)(you)(you)那么多的(de)有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)了(le)——因為(wei)它體積(ji)比較小，同時又因為(wei)這(zhe)樣(yang)的(de)電(dian)(dian)(dian)(dian)(dian)路中電(dian)(dian)(dian)(dian)(dian)壓只(zhi)有(you)(you)(you)一(yi)個(ge)方向，所以(yi)(yi)有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)就(jiu)(jiu)(jiu)能(neng)派上用(yong)場。我(wo)們(men)使(shi)用(yong)有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，就(jiu)(jiu)(jiu)是(shi)避開(kai)它的(de)缺點(dian)，利用(yong)它的(de)優點(dian)。我(wo)們(men)可以(yi)(yi)這(zhe)樣(yang)來理解(jie)：有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)實(shi)際(ji)上是(shi)一(yi)個(ge)只(zhi)能(neng)按一(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)壓方向使(shi)用(yong)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)。而無極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，則(ze)兩個(ge)電(dian)(dian)(dian)(dian)(dian)壓方向都能(neng)使(shi)用(yong)。因此(ci)，單從(cong)電(dian)(dian)(dian)(dian)(dian)壓方向這(zhe)一(yi)點(dian)上來說，無極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)是(shi)比有(you)(you)(you)極(ji)(ji)性(xing)(xing)(xing)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)要(yao)好的(de)。

從上面的分析可以看出來，使用無極性的電容代(dai)替有極性的電容(rong)是(shi)完全可(ke)以的——只要(yao)(yao)容(rong)量、工作電壓(ya)、體(ti)積等能滿足要(yao)(yao)求即可(ke)替換。