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，雖然確實存在著無極(ji)(ji)性(xing)(xing)電(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)容，但在市面上不太常(chang)見，而且價格(ge)也(ye)比較貴。常(chang)見的(de)電(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)容都(dou)是由(you)陽極(ji)(ji)鋁箔(bo)和陰(yin)極(ji)(ji)的(de)電(dian)(dian)(dian)解(jie)溶(rong)液分別形成兩(liang)個電(dian)(dian)(dian)極(ji)(ji)，由(you)陽極(ji)(ji)鋁箔(bo)上產生的(de)一層(ceng)氧化鋁膜做為電(dian)(dian)(dian)介質的(de)電(dian)(dian)(dian)容，電(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)容在電(dian)(dian)(dian)路中也(ye)必須注(zhu)意極(ji)(ji)性(xing)(xing)。

普通的(de)電(dian)(dian)容(rong)是(shi)(shi)大(da)部分(fen)(fen)是(shi)(shi)無(wu)極(ji)(ji)性的(de)，也可以(yi)把兩個(ge)電(dian)(dian)解(jie)電(dian)(dian)容(rong)陽極(ji)(ji)或(huo)陰極(ji)(ji)相(xiang)對串連形成無(wu)極(ji)(ji)性電(dian)(dian)解(jie)電(dian)(dian)容(rong)。一(yi)般(ban)來說，低于(yu)1μF的(de)低值電(dian)(dian)容(rong)大(da)多數是(shi)(shi)無(wu)極(ji)(ji)性之(zhi)分(fen)(fen)的(de)，但是(shi)(shi)具有1μF或(huo)更大(da)電(dian)(dian)容(rong)值的(de)電(dian)(dian)容(rong)幾(ji)乎都(dou)是(shi)(shi)有正負極(ji)(ji)之(zhi)分(fen)(fen)的(de)。至今為止(zhi)，常用(yong)有極(ji)(ji)性電(dian)(dian)容(rong)是(shi)(shi)電(dian)(dian)解(jie)電(dian)(dian)容(rong)，有極(ji)(ji)性電(dian)(dian)容(rong)的(de)正引線總會長一(yi)些，即(ji)使是(shi)(shi)標志磨損(sun)或(huo)者被完(wan)全抹去，我(wo)們也能夠辨(bian)認出極(ji)(ji)性。

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二、電解電容和普通電容的區別

1、介質不同

有(you)(you)極性電容(rong)大(da)多(duo)采用(yong)(yong)電解質(zhi)做(zuo)介(jie)質(zhi)材(cai)料(liao)(liao)，通常同體(ti)積的電容(rong)有(you)(you)極性電容(rong)容(rong)量大(da)。另外，不(bu)同的電解質(zhi)材(cai)料(liao)(liao)和(he)(he)工(gong)藝制造(zao)出的有(you)(you)極性電容(rong)同體(ti)積的容(rong)量也會不(bu)同。再(zai)有(you)(you)就是耐壓和(he)(he)使用(yong)(yong)介(jie)質(zhi)材(cai)料(liao)(liao)也有(you)(you)密切關系(xi)。無極性電容(rong)介(jie)質(zhi)材(cai)料(liao)(liao)也很多(duo)，大(da)多(duo)采用(yong)(yong)金屬氧化(hua)膜(mo)、滌綸等。由于(yu)介(jie)質(zhi)的可(ke)逆或不(bu)可(ke)逆性能決定了有(you)(you)極、無極性電容(rong)的使用(yong)(yong)環境。

2、性能不同

性能就(jiu)是(shi)使(shi)用(yong)(yong)(yong)(yong)的(de)(de)(de)要(yao)求，需求最(zui)大化就(jiu)是(shi)使(shi)用(yong)(yong)(yong)(yong)的(de)(de)(de)要(yao)求。如果在電(dian)視(shi)機(ji)里電(dian)源(yuan)(yuan)部分用(yong)(yong)(yong)(yong)金屬氧(yang)化膜電(dian)容(rong)器(qi)做濾(lv)波(bo)(bo)的(de)(de)(de)話，而(er)且要(yao)達(da)到(dao)濾(lv)波(bo)(bo)要(yao)求的(de)(de)(de)電(dian)容(rong)器(qi)容(rong)量和耐壓。機(ji)殼內恐怕也(ye)就(jiu)只能裝個電(dian)源(yuan)(yuan)了。所以作(zuo)為濾(lv)波(bo)(bo)只能使(shi)用(yong)(yong)(yong)(yong)有(you)極性電(dian)容(rong)，有(you)極性電(dian)容(rong)是(shi)不(bu)可(ke)逆的(de)(de)(de)。就(jiu)是(shi)說正極必須接高電(dian)位端(duan)(duan)，負(fu)極必須接低電(dian)位端(duan)(duan)。一般電(dian)解電(dian)容(rong)在1微法拉以上，做偶(ou)(ou)合、退偶(ou)(ou)合、電(dian)源(yuan)(yuan)濾(lv)波(bo)(bo)等(deng)。無(wu)極性電(dian)容(rong)大多在1微法拉以下，參與諧振、偶(ou)(ou)合、選頻(pin)、限流(liu)、等(deng)。當然也(ye)有(you)大容(rong)量高耐壓的(de)(de)(de)，多用(yong)(yong)(yong)(yong)在電(dian)力的(de)(de)(de)無(wu)功補(bu)償、電(dian)機(ji)的(de)(de)(de)移(yi)相、變頻(pin)電(dian)源(yuan)(yuan)移(yi)相等(deng)用(yong)(yong)(yong)(yong)途上。

3、容量不同

電解(jie)電容的容量要比普通電容大(da)。

4、結構不同

原則(ze)上講(jiang)不考慮尖端放電(dian)的情況下(xia)，使(shi)用(yong)環(huan)境需要(yao)什么形狀的電(dian)容都(dou)可(ke)(ke)以。通常用(yong)的電(dian)解電(dian)容（有(you)極性電(dian)容）是圓(yuan)形，方(fang)型(xing)用(yong)的很少。無極性電(dian)容形狀千(qian)奇百變。像管型(xing)、變形長方(fang)形、片型(xing)、方(fang)型(xing)、圓(yuan)型(xing)、組合方(fang)型(xing)及圓(yuan)型(xing)等(deng)等(deng)。當(dang)然還(huan)有(you)無形的，這里無形指的就是分布(bu)電(dian)容。對于分布(bu)電(dian)容在高頻(pin)和中頻(pin)器(qi)件中決(jue)不可(ke)(ke)忽(hu)視。

三、無極性電容可以代替有極性電容嗎

理想的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，本來(lai)是(shi)(shi)沒有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)。但是(shi)(shi)在實(shi)際(ji)中(zhong)，為(wei)了獲得大容(rong)(rong)(rong)(rong)(rong)量(liang)，就(jiu)(jiu)使用(yong)(yong)(yong)了某些(xie)特殊(shu)的(de)(de)材料(liao)和結構，這(zhe)就(jiu)(jiu)導致了實(shi)際(ji)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)有(you)些(xie)是(shi)(shi)有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)。常見(jian)的(de)(de)有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)有(you)鋁電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，鉭電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)等。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)一(yi)(yi)般是(shi)(shi)容(rong)(rong)(rong)(rong)(rong)量(liang)相(xiang)對(dui)比(bi)較大的(de)(de)。如果要做(zuo)一(yi)(yi)個(ge)(ge)大容(rong)(rong)(rong)(rong)(rong)量(liang)的(de)(de)無極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，就(jiu)(jiu)沒那(nei)(nei)么容(rong)(rong)(rong)(rong)(rong)易(yi)了，體(ti)積(ji)會變得很大。這(zhe)就(jiu)(jiu)是(shi)(shi)為(wei)什么在實(shi)際(ji)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)，為(wei)什么會有(you)那(nei)(nei)么多的(de)(de)有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)了——因為(wei)它(ta)體(ti)積(ji)比(bi)較小，同時又因為(wei)這(zhe)樣(yang)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)只有(you)一(yi)(yi)個(ge)(ge)方(fang)向，所以有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)就(jiu)(jiu)能派上(shang)(shang)用(yong)(yong)(yong)場。我們(men)使用(yong)(yong)(yong)有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，就(jiu)(jiu)是(shi)(shi)避開(kai)它(ta)的(de)(de)缺點，利用(yong)(yong)(yong)它(ta)的(de)(de)優點。我們(men)可以這(zhe)樣(yang)來(lai)理解(jie)：有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)實(shi)際(ji)上(shang)(shang)是(shi)(shi)一(yi)(yi)個(ge)(ge)只能按一(yi)(yi)個(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)方(fang)向使用(yong)(yong)(yong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)。而無極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，則(ze)兩(liang)個(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)方(fang)向都能使用(yong)(yong)(yong)。因此，單從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)方(fang)向這(zhe)一(yi)(yi)點上(shang)(shang)來(lai)說，無極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)是(shi)(shi)比(bi)有(you)極(ji)(ji)(ji)(ji)性(xing)(xing)(xing)(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)要好的(de)(de)。

從上面的分析可以看出來，使用無極性的電容代替有極性的電容是完全(quan)可(ke)以的——只(zhi)要容量、工作電壓(ya)、體積等能滿足要求即(ji)可(ke)替換。