NEWS
穿心電容知識
您所在的位置:
首頁 >
新聞資訊
> 穿心電容知識
剖析穿心電容的選用方法
這里需要解釋一下,在實際應用中,穿心電容并不是一個純電容,其內部還有等效電阻,它的簡化等效電路如下所示。C為穿心電容的實際電容量,Rs是穿心電容的串聯等效電阻,Rp是介質的絕緣電阻,Ro是介質的吸收等效電阻。對于電子設備來說,要求Rs愈小愈好,也就是說要求損耗功率小,其與電容的功率的夾角δ要小。
對于(yu)可變穿(chuan)心(xin)電(dian)(dian)(dian)(dian)容(rong),應根據(ju)電(dian)(dian)(dian)(dian)容(rong)統調的級數,確定應采用單聯或(huo)多聯的可變穿(chuan)心(xin)電(dian)(dian)(dian)(dian)容(rong),然后根據(ju)容(rong)量(liang)的變化范圍、容(rong)量(liang)變化曲線、體(ti)積(ji)等要求確定相應品種的穿(chuan)心(xin)電(dian)(dian)(dian)(dian)容(rong)。 在電(dian)(dian)(dian)(dian)源濾波和退(tui)耦電(dian)(dian)(dian)(dian)路中(zhong),可選用電(dian)(dian)(dian)(dian)解(jie)穿(chuan)心(xin)電(dian)(dian)(dian)(dian)容(rong)。因為在這些(xie)使用場合,對穿(chuan)心(xin)電(dian)(dian)(dian)(dian)容(rong)性能要求不高,只要體(ti)積(ji)不大(da),容(rong)量(liang)夠用就可以了。
電(dian)容在電(dian)路中一般用“C”加數字表(biao)示(如C13表(biao)示編號為13的電(dian)容)。電(dian)容是(shi)由兩片金屬膜緊靠,中間(jian)用絕緣材(cai)料(liao)隔開而組(zu)成的元件。電(dian)容的特性主要是(shi)隔直流(liu)通交(jiao)流(liu)。
根據電(dian)路(lu)要(yao)求,一(yi)般用于低頻耦合、旁(pang)路(lu)去耦等,電(dian)氣(qi)性能要(yao)求較低時(shi),可以采用紙介穿(chuan)心電(dian)容、電(dian)解穿(chuan)心電(dian)容等。
晶體管低頻(pin)放大器的(de)耦合(he)穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong),選(xuan)用(yong)(yong)1~22μF的(de)電(dian)(dian)解穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong)。旁(pang)路穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong)根據電(dian)(dian)路的(de)工作頻(pin)率來選(xuan),如(ru)在(zai)(zai)低頻(pin)電(dian)(dian)路中,發射極旁(pang)路電(dian)(dian)容(rong)選(xuan)用(yong)(yong)電(dian)(dian)解穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong),容(rong)量在(zai)(zai)10~220μF之(zhi)間;在(zai)(zai)中頻(pin)電(dian)(dian)路中,可(ke)選(xuan)用(yong)(yong)0.01~0.1μF的(de)紙介(jie)、金屬化紙介(jie)、有機薄膜穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong)等;在(zai)(zai)高(gao)頻(pin)電(dian)(dian)路中應(ying)選(xuan)擇高(gao)頻(pin)瓷(ci)介(jie)質穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong);若要(yao)求(qiu)在(zai)(zai)高(gao)溫下工作,則應(ying)選(xuan)玻璃(li)釉穿(chuan)(chuan)(chuan)心(xin)(xin)電(dian)(dian)容(rong)等。