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(cun)在著無極(ji)(ji)性電(dian)(dian)解電(dian)(dian)容，但在市面(mian)上不太常(chang)(chang)見，而且價格也(ye)比較貴。常(chang)(chang)見的電(dian)(dian)解電(dian)(dian)容都是由(you)陽極(ji)(ji)鋁箔(bo)(bo)和(he)陰極(ji)(ji)的電(dian)(dian)解溶液分(fen)別形(xing)成兩(liang)個電(dian)(dian)極(ji)(ji)，由(you)陽極(ji)(ji)鋁箔(bo)(bo)上產生(sheng)的一層氧化鋁膜(mo)做為電(dian)(dian)介質的電(dian)(dian)容，電(dian)(dian)解電(dian)(dian)容在電(dian)(dian)路中也(ye)必須注意(yi)極(ji)(ji)性。

普通的電(dian)(dian)容(rong)(rong)是(shi)(shi)大部(bu)分(fen)是(shi)(shi)無(wu)極(ji)性(xing)的，也(ye)可以把兩個電(dian)(dian)解電(dian)(dian)容(rong)(rong)陽極(ji)或陰(yin)極(ji)相對串(chuan)連形成無(wu)極(ji)性(xing)電(dian)(dian)解電(dian)(dian)容(rong)(rong)。一般來說，低于1μF的低值(zhi)電(dian)(dian)容(rong)(rong)大多數是(shi)(shi)無(wu)極(ji)性(xing)之分(fen)的，但是(shi)(shi)具有1μF或更大電(dian)(dian)容(rong)(rong)值(zhi)的電(dian)(dian)容(rong)(rong)幾乎(hu)都(dou)是(shi)(shi)有正負極(ji)之分(fen)的。至今為止，常用(yong)有極(ji)性(xing)電(dian)(dian)容(rong)(rong)是(shi)(shi)電(dian)(dian)解電(dian)(dian)容(rong)(rong)，有極(ji)性(xing)電(dian)(dian)容(rong)(rong)的正引線總會長一些，即使是(shi)(shi)標志磨損或者(zhe)被完全(quan)抹去(qu)，我們也(ye)能夠辨認出極(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)(you)極(ji)性(xing)電(dian)容(rong)大多(duo)采(cai)用電(dian)解(jie)質做介質材(cai)料(liao)，通常同(tong)體(ti)積(ji)的(de)(de)電(dian)容(rong)有(you)(you)極(ji)性(xing)電(dian)容(rong)容(rong)量大。另外，不同(tong)的(de)(de)電(dian)解(jie)質材(cai)料(liao)和工藝制(zhi)造出的(de)(de)有(you)(you)極(ji)性(xing)電(dian)容(rong)同(tong)體(ti)積(ji)的(de)(de)容(rong)量也會(hui)不同(tong)。再有(you)(you)就(jiu)是耐壓和使(shi)用介質材(cai)料(liao)也有(you)(you)密(mi)切關系。無極(ji)性(xing)電(dian)容(rong)介質材(cai)料(liao)也很(hen)多(duo)，大多(duo)采(cai)用金屬氧(yang)化膜、滌(di)綸等(deng)。由(you)于(yu)介質的(de)(de)可逆或不可逆性(xing)能決定了(le)有(you)(you)極(ji)、無極(ji)性(xing)電(dian)容(rong)的(de)(de)使(shi)用環境。

2、性能不同

性能(neng)就(jiu)是使(shi)(shi)用(yong)(yong)的(de)(de)(de)要求(qiu)(qiu)，需求(qiu)(qiu)最(zui)大化就(jiu)是使(shi)(shi)用(yong)(yong)的(de)(de)(de)要求(qiu)(qiu)。如(ru)果在電(dian)(dian)(dian)(dian)(dian)(dian)視機里電(dian)(dian)(dian)(dian)(dian)(dian)源部分用(yong)(yong)金屬氧化膜電(dian)(dian)(dian)(dian)(dian)(dian)容器做(zuo)濾(lv)(lv)波的(de)(de)(de)話(hua)，而且(qie)要達到濾(lv)(lv)波要求(qiu)(qiu)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容器容量(liang)和耐(nai)壓。機殼內恐(kong)怕也就(jiu)只能(neng)裝個電(dian)(dian)(dian)(dian)(dian)(dian)源了(le)。所以作為濾(lv)(lv)波只能(neng)使(shi)(shi)用(yong)(yong)有(you)極(ji)(ji)性電(dian)(dian)(dian)(dian)(dian)(dian)容，有(you)極(ji)(ji)性電(dian)(dian)(dian)(dian)(dian)(dian)容是不(bu)可逆的(de)(de)(de)。就(jiu)是說正極(ji)(ji)必(bi)須(xu)(xu)接高(gao)電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)端(duan)，負極(ji)(ji)必(bi)須(xu)(xu)接低電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)端(duan)。一般電(dian)(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)(dian)容在1微法拉(la)以上(shang)(shang)，做(zuo)偶(ou)合、退偶(ou)合、電(dian)(dian)(dian)(dian)(dian)(dian)源濾(lv)(lv)波等。無極(ji)(ji)性電(dian)(dian)(dian)(dian)(dian)(dian)容大多在1微法拉(la)以下，參與諧振、偶(ou)合、選頻(pin)、限流(liu)、等。當然(ran)也有(you)大容量(liang)高(gao)耐(nai)壓的(de)(de)(de)，多用(yong)(yong)在電(dian)(dian)(dian)(dian)(dian)(dian)力的(de)(de)(de)無功補償、電(dian)(dian)(dian)(dian)(dian)(dian)機的(de)(de)(de)移(yi)相、變頻(pin)電(dian)(dian)(dian)(dian)(dian)(dian)源移(yi)相等用(yong)(yong)途上(shang)(shang)。

3、容量不同

電(dian)解電(dian)容的(de)容量要比普(pu)通電(dian)容大(da)。

4、結構不同

原(yuan)則上講不(bu)考(kao)慮尖端(duan)放(fang)電(dian)(dian)的(de)(de)(de)情況下，使用(yong)環境需要什么形(xing)(xing)(xing)狀的(de)(de)(de)電(dian)(dian)容都可(ke)(ke)以(yi)。通常用(yong)的(de)(de)(de)電(dian)(dian)解電(dian)(dian)容（有極性電(dian)(dian)容）是(shi)圓形(xing)(xing)(xing)，方(fang)型(xing)用(yong)的(de)(de)(de)很少。無極性電(dian)(dian)容形(xing)(xing)(xing)狀千奇百變(bian)。像(xiang)管型(xing)、變(bian)形(xing)(xing)(xing)長(chang)方(fang)形(xing)(xing)(xing)、片型(xing)、方(fang)型(xing)、圓型(xing)、組合方(fang)型(xing)及圓型(xing)等(deng)等(deng)。當(dang)然還(huan)有無形(xing)(xing)(xing)的(de)(de)(de)，這里無形(xing)(xing)(xing)指的(de)(de)(de)就是(shi)分布電(dian)(dian)容。對(dui)于分布電(dian)(dian)容在高頻和中(zhong)頻器件中(zhong)決不(bu)可(ke)(ke)忽視(shi)。

三、無極性電容可以代替有極性電容嗎

理(li)(li)想(xiang)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)，本來(lai)是(shi)(shi)沒(mei)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)。但是(shi)(shi)在(zai)實(shi)際中，為(wei)(wei)了獲得大(da)容(rong)(rong)(rong)量(liang)，就使用(yong)了某些特(te)殊的(de)(de)(de)(de)材料和(he)結構，這(zhe)(zhe)就導致了實(shi)際的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)有(you)(you)(you)(you)些是(shi)(shi)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)。常見的(de)(de)(de)(de)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)有(you)(you)(you)(you)鋁電(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)，鉭電(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)等。電(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)一般是(shi)(shi)容(rong)(rong)(rong)量(liang)相對比(bi)較大(da)的(de)(de)(de)(de)。如(ru)果要(yao)做一個大(da)容(rong)(rong)(rong)量(liang)的(de)(de)(de)(de)無極(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)，就沒(mei)那(nei)么容(rong)(rong)(rong)易了，體積會變得很大(da)。這(zhe)(zhe)就是(shi)(shi)為(wei)(wei)什么在(zai)實(shi)際的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)路(lu)中，為(wei)(wei)什么會有(you)(you)(you)(you)那(nei)么多(duo)的(de)(de)(de)(de)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)了——因為(wei)(wei)它(ta)(ta)體積比(bi)較小，同時又因為(wei)(wei)這(zhe)(zhe)樣的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)路(lu)中電(dian)(dian)(dian)(dian)壓(ya)只有(you)(you)(you)(you)一個方向(xiang)，所以(yi)(yi)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)就能(neng)派上(shang)用(yong)場。我們使用(yong)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)，就是(shi)(shi)避(bi)開它(ta)(ta)的(de)(de)(de)(de)缺點，利用(yong)它(ta)(ta)的(de)(de)(de)(de)優點。我們可以(yi)(yi)這(zhe)(zhe)樣來(lai)理(li)(li)解(jie)：有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)實(shi)際上(shang)是(shi)(shi)一個只能(neng)按一個電(dian)(dian)(dian)(dian)壓(ya)方向(xiang)使用(yong)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)。而無極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)，則兩個電(dian)(dian)(dian)(dian)壓(ya)方向(xiang)都能(neng)使用(yong)。因此(ci)，單從電(dian)(dian)(dian)(dian)壓(ya)方向(xiang)這(zhe)(zhe)一點上(shang)來(lai)說(shuo)，無極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)是(shi)(shi)比(bi)有(you)(you)(you)(you)極(ji)性(xing)(xing)(xing)(xing)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)要(yao)好的(de)(de)(de)(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(dian)容是完全可以的——只要容量、工(gong)作(zuo)電(dian)壓、體積等能(neng)滿足要求(qiu)即(ji)可替換。