對(dui)電(dian)路中電(dian)容元件的選(xuan)用應(ying)該考慮(lv)以下幾個(ge)因(yin)素(su)：

電子開發電容耐壓選擇

電(dian)(dian)子產品開發在選(xuan)用電(dian)(dian)容時，元件的耐壓(ya)一(yi)定要高于實(shi)際電(dian)(dian)路(lu)中的工(gong)作電(dian)(dian)壓(ya)，尤其值得注意的是電(dian)(dian)子電(dian)(dian)路(lu)中要考慮(lv)到可能產生的高壓(ya)。

電子開發電容電容量選擇

在(zai)(zai)電(dian)子(zi)電(dian)路，電(dian)容量是根據(ju)某些性能(neng)指(zhi)標確(que)定(ding)的(de)(de)，在(zai)(zai)確(que)定(ding)容量時要根據(ju)標稱系(xi)列選擇。如果通(tong)(tong)過(guo)標稱系(xi)列找不到該電(dian)容的(de)(de)容量數(shu)值，可以(yi)通(tong)(tong)過(guo)串并聯的(de)(de)方(fang)(fang)法(fa)解(jie)決(jue)或通(tong)(tong)過(guo)修改設計方(fang)(fang)案中其他參數(shu)加以(yi)解(jie)決(jue)。在(zai)(zai)更(geng)換電(dian)路中的(de)(de)電(dian)容時最好選用原參數(shu)的(de)(de)電(dian)容或性能(neng)指(zhi)標優于原電(dian)路電(dian)容的(de)(de)元件(jian)。

電子開發電容介質選擇

電容(rong)介質不(bu)同，其特(te)性(xing)差異(yi)較(jiao)大，用(yong)途(tu)也(ye)不(bu)完全相同。在選用(yong)電容(rong)的介質時，要首(shou)先了解各(ge)介質的特(te)性(xing)，然后確定適用(yong)何種(zhong)場合。下面分別(bie)介紹幾種(zhong)常用(yong)的固定電容(rong)的使用(yong)。

電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)是(shi)以鋁等(deng)金屬(shu)為(wei)(wei)正(zheng)極(ji)(ji)(ji)，在其表面(mian)形成(cheng)一層氧化(hua)膜為(wei)(wei)介質，介質與電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)成(cheng)為(wei)(wei)不(bu)可分的整體(ti)；負極(ji)(ji)(ji)是(shi)固體(ti)或(huo)非固體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)質。由(you)于構(gou)成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的兩電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)的材料(liao)不(bu)同，因此它的正(zheng)負電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)分別標出，使用時一定要正(zheng)極(ji)(ji)(ji)端(duan)接(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)路的高電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)，負極(ji)(ji)(ji)端(duan)接(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)路的低(di)電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)，否(fou)則會引起電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的損壞。按照電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)材料(liao)的不(bu)同有鋁電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)、鉭電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)和(he)鈮電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)等(deng)幾種。

云母電容是以(yi)云母片為介質(zhi)的電容。它絕緣性能好(hao)、損耗小、溫(wen)度穩(wen)定性好(hao)、電容量精確(que)度高，常(chang)用(yong)在高頻振蕩電路中。

瓷(ci)(ci)介電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)的(de)介質是陶瓷(ci)(ci)，根據陶瓷(ci)(ci)成分不同可分為(wei)高(gao)頻(pin)瓷(ci)(ci)介電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)和低(di)頻(pin)瓷(ci)(ci)介電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)兩種(zhong)（高(gao)頻(pin)的(de)用(yong)CC表示，低(di)頻(pin)的(de)用(yong)CT表示）。高(gao)頻(pin)瓷(ci)(ci)介電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)在零點幾(ji)皮法至幾(ji)百皮法之間。常使用(yong)于要求損耗小(xiao)、電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)穩定的(de)場合和在高(gao)頻(pin)電(dian)(dian)(dian)路中作調諧電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)、振蕩回路電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)和溫度補償電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)。電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)耐(nai)壓有(you) 160V、250V和 500V等幾(ji)種(zhong)。容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)誤差分為(wei)2%、5%、10%和20%幾(ji)種(zhong)。低(di)頻(pin)瓷(ci)(ci)介電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)從300pF到22000pF之間，適用(yong)于低(di)頻(pin)電(dian)(dian)(dian)路中。

紙介電容(rong)生產工藝簡單，成本低，電壓范圍較(jiao)(jiao)寬；缺點是(shi)電容(rong)量不易控制，損耗較(jiao)(jiao)大，穩定性較(jiao)(jiao)差，電感最大，通常不適宜在高頻(pin)下使用。

滌綸(lun)電(dian)(dian)容(rong)(rong)又叫(jiao)聚酯電(dian)(dian)容(rong)(rong)。它是以滌綸(lun)薄膜做介質的(de)電(dian)(dian)容(rong)(rong)。它可用于各(ge)種電(dian)(dian)子儀器儀表，電(dian)(dian)視機、收錄(lu)機的(de)耦合、退(tui)耦、旁路、隔直流(liu)等電(dian)(dian)路中。

聚(ju)苯乙(yi)烯(xi)電(dian)容是以(yi)聚(ju)苯乙(yi)烯(xi)薄(bo)膜為介質(zhi)制成(cheng)的(de)(de)(de)電(dian)容。聚(ju)苯乙(yi)烯(xi)電(dian)容的(de)(de)(de)最大特點是絕緣電(dian)阻高。這種電(dian)容的(de)(de)(de)高頻損(sun)耗小，電(dian)容量穩(wen)定，是目前應用廣泛的(de)(de)(de)一種電(dian)容，由于其精(jing)度高，在(zai)濾(lv)波(bo)器及對(dui)容量要求精(jing)確的(de)(de)(de)電(dian)路中（如電(dian)子琴電(dian)路）多(duo)采用。它的(de)(de)(de)缺(que)點是工(gong)作溫度范圍不(bu)寬，上(shang)限為+75℃。因此(ci)焊接時烙鐵(tie)的(de)(de)(de)接觸時間不(bu)宜(yi)過(guo)長(chang)，以(yi)免因過(guo)熱損(sun)壞(huai)薄(bo)膜。