在為耦合/隔直(zhi)應用選擇電(dian)容(rong)器時,要(yao)考(kao)慮(lv)的(de)關鍵參數(shu)包括阻抗、等效串聯電(dian)阻和串聯諧振(zhen)頻率(lv)。電(dian)容(rong)值主要(yao)取決于(yu)(yu)應用的(de)頻率(lv)范圍(wei)和負載(zai)/源阻抗。通常用于(yu)(yu)耦合應用的(de)電(dian)容(rong)器類型包括薄膜、陶瓷、鉭、鋁電(dian)解和鋁有(you)機/聚(ju)合物電(dian)解電(dian)容(rong)器。
鉭(tan)電(dian)(dian)容(rong)(rong)器(qi)在高(gao)電(dian)(dian)容(rong)(rong)值(zhi)下提供高(gao)穩定性,并且它們(men)有(you)不(bu)同的變(bian)體(ti)。與陶瓷電(dian)(dian)容(rong)(rong)器(qi)相比(bi)(bi),這些電(dian)(dian)容(rong)(rong)器(qi)具有(you)更(geng)高(gao)的 ESR 并且更(geng)昂(ang)貴。對(dui)于耦合應用,鉭(tan)電(dian)(dian)容(rong)(rong)器(qi)比(bi)(bi)陶瓷電(dian)(dian)容(rong)(rong)器(qi)更(geng)受歡(huan)迎。
鋁電解(jie)電容(rong)(rong)器(qi)(qi)比鉭(tan)電容(rong)(rong)器(qi)(qi)便宜。它們(men)提供(gong)穩定的(de)電容(rong)(rong)并(bing)具(ju)有類似于鉭(tan)電容(rong)(rong)器(qi)(qi)的(de) ESR 特性。但是,這些電容(rong)(rong)器(qi)(qi)的(de)尺(chi)寸相對較大(da),不推薦(jian)用于電路板空間(jian)有限的(de)電路。鋁電解(jie)電容(rong)(rong)器(qi)(qi)廣(guang)泛用于功率放大(da)器(qi)(qi)中(zhong)的(de)耦合應(ying)用。
陶瓷(ci)電(dian)(dian)容器價格低廉,采用(yong)(yong)小(xiao)型 SMT 封裝。與鉭(tan)電(dian)(dian)容器相比,這(zhe)些電(dian)(dian)容器更(geng)便宜(yi)。盡管陶瓷(ci)電(dian)(dian)容器通(tong)(tong)常(chang)用(yong)(yong)于音頻(pin)和射頻(pin)應用(yong)(yong),但它們通(tong)(tong)常(chang)不適(shi)用(yong)(yong)于需要卓越性能(neng)的應用(yong)(yong)。
薄膜電容器(qi)的(de)(de)大物理尺寸(cun)限制了它們在交流耦合(he)中的(de)(de)應(ying)用(yong)。如果空間不是問題,聚丙烯和(he)聚酯電容器(qi)的(de)(de)特性使其成為前置放(fang)大器(qi)電路(lu)中耦合(he)應(ying)用(yong)的(de)(de)良好選擇。