一、電解電容在電路中的作用 1,濾(lv)波作用,在(zai)電(dian)(dian)(dian)源電(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong),整(zheng)流(liu)(liu)電(dian)(dian)(dian)路(lu)(lu)(lu)將(jiang)交流(liu)(liu)變(bian)成脈動的(de)(de)直(zhi)流(liu)(liu),而在(zai)整(zheng)流(liu)(liu)電(dian)(dian)(dian)路(lu)(lu)(lu)之后(hou)(hou)接(jie)入一個(ge)較大容(rong)(rong)量(liang)(liang)的(de)(de)電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容(rong)(rong),利用其充放電(dian)(dian)(dian)特性,使整(zheng)流(liu)(liu)后(hou)(hou)的(de)(de)脈動直(zhi)流(liu)(liu)電(dian)(dian)(dian)壓變(bian)成相(xiang)對比較穩定的(de)(de)直(zhi)流(liu)(liu)電(dian)(dian)(dian)壓。在(zai)實際中(zhong),為(wei)(wei)了(le)防止(zhi)電(dian)(dian)(dian)路(lu)(lu)(lu)各部分(fen)供電(dian)(dian)(dian)電(dian)(dian)(dian)壓因負載變(bian)化(hua)而產生變(bian)化(hua),所以(yi)在(zai)電(dian)(dian)(dian)源的(de)(de)輸出(chu)端及負載的(de)(de)電(dian)(dian)(dian)源輸入端一般接(jie)有數(shu)十(shi)至數(shu)百微法的(de)(de)電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容(rong)(rong).由于大容(rong)(rong)量(liang)(liang)的(de)(de)電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容(rong)(rong)一般具有一定的(de)(de)電(dian)(dian)(dian)感(gan),對高頻(pin)及脈沖干擾信號不能(neng)有效地(di)濾(lv)除,故在(zai)其兩端并聯了(le)一只容(rong)(rong)量(liang)(liang)為(wei)(wei)0.001--0.lpF的(de)(de)電(dian)(dian)(dian)容(rong)(rong),以(yi)濾(lv)除高頻(pin)及脈沖干擾.
2,耦合(he)作用:在(zai)低頻(pin)信號的傳遞與(yu)放大(da)過程中,為防(fang)止前后兩級電(dian)路的靜態工作點(dian)相互影響,常采用電(dian)容藕合(he).為了防(fang)止信號中韻(yun)低頻(pin)分量(liang)損失過大(da),一般總采用容量(liang)較大(da)的電(dian)解電(dian)容。
二、電解電容的判斷方法 電(dian)(dian)(dian)(dian)解(jie)(jie)(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)常見(jian)的(de)(de)(de)(de)(de)(de)故障有,容(rong)(rong)量(liang)(liang)(liang)(liang)減少,容(rong)(rong)量(liang)(liang)(liang)(liang)消失(shi)、擊(ji)(ji)穿(chuan)短路(lu)及漏電(dian)(dian)(dian)(dian),其(qi)(qi)中(zhong)容(rong)(rong)量(liang)(liang)(liang)(liang)變(bian)化是因電(dian)(dian)(dian)(dian)解(jie)(jie)(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)在(zai)使(shi)用或放置過(guo)程中(zhong)其(qi)(qi)內(nei)部的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)解(jie)(jie)(jie)液(ye)逐漸干涸引(yin)起,而(er)擊(ji)(ji)穿(chuan)與漏電(dian)(dian)(dian)(dian)一(yi)般(ban)為所加的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓過(guo)高(gao)或本身質(zhi)量(liang)(liang)(liang)(liang)不佳引(yin)起。判斷(duan)電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)(de)(de)(de)好(hao)壞(huai)一(yi)般(ban)采用萬(wan)(wan)用表(biao)(biao)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)檔(dang)進(jin)行測(ce)量(liang)(liang)(liang)(liang).具體方法為:將電(dian)(dian)(dian)(dian)容(rong)(rong)兩管腳(jiao)短路(lu)進(jin)行放電(dian)(dian)(dian)(dian),用萬(wan)(wan)用表(biao)(biao)的(de)(de)(de)(de)(de)(de)黑表(biao)(biao)筆(bi)接電(dian)(dian)(dian)(dian)解(jie)(jie)(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)(de)(de)(de)正極。紅表(biao)(biao)筆(bi)接負極(對指針(zhen)(zhen)式(shi)萬(wan)(wan)用表(biao)(biao),用數(shu)字式(shi)萬(wan)(wan)用表(biao)(biao)測(ce)量(liang)(liang)(liang)(liang)時(shi)表(biao)(biao)筆(bi)互調),正常時(shi)表(biao)(biao)針(zhen)(zhen)應先向(xiang)電(dian)(dian)(dian)(dian)阻(zu)小(xiao)的(de)(de)(de)(de)(de)(de)方向(xiang)擺動,然(ran)后逐漸返(fan)回直至(zhi)無窮大處。表(biao)(biao)針(zhen)(zhen)的(de)(de)(de)(de)(de)(de)擺動幅度越大或返(fan)回的(de)(de)(de)(de)(de)(de)速度越慢,說(shuo)明電(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)(de)(de)(de)容(rong)(rong)量(liang)(liang)(liang)(liang)越大,反之則說(shuo)明電(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)(de)(de)(de)容(rong)(rong)量(liang)(liang)(liang)(liang)越小(xiao).如表(biao)(biao)針(zhen)(zhen)指在(zai)中(zhong)間某處不再變(bian)化,說(shuo)明此電(dian)(dian)(dian)(dian)容(rong)(rong)漏電(dian)(dian)(dian)(dian),如電(dian)(dian)(dian)(dian)阻(zu)指示值(zhi)很(hen)小(xiao)或為零,則表(biao)(biao)明此電(dian)(dian)(dian)(dian)容(rong)(rong)已擊(ji)(ji)穿(chuan)短路(lu).因萬(wan)(wan)用表(biao)(biao)使(shi)用的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓一(yi)般(ban)很(hen)低,所以在(zai)測(ce)量(liang)(liang)(liang)(liang)低耐壓的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)時(shi)比較(jiao)準(zhun)確,而(er)當電(dian)(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)(de)(de)(de)耐壓較(jiao)高(gao)時(shi),打時(shi)盡管測(ce)量(liang)(liang)(liang)(liang)正常,但加上高(gao)壓時(shi)則有可(ke)能發(fa)生漏電(dian)(dian)(dian)(dian)或擊(ji)(ji)穿(chuan)現象.
三、電解電容的使用注意事項 1、電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)由于(yu)(yu)有正(zheng)負極(ji)性,因此在電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong)使(shi)用時(shi)不(bu)能顛(dian)倒聯接(jie)(jie)(jie)。在電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong),輸(shu)(shu)出(chu)(chu)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)壓時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的(de)正(zheng)極(ji)接(jie)(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)輸(shu)(shu)出(chu)(chu)端,負極(ji)接(jie)(jie)(jie)地,輸(shu)(shu)出(chu)(chu)負電(dian)(dian)(dian)(dian)(dian)(dian)壓時(shi)則負極(ji)接(jie)(jie)(jie)輸(shu)(shu)出(chu)(chu)端,正(zheng)極(ji)接(jie)(jie)(jie)地.當電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong)的(de)濾波電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)極(ji)性接(jie)(jie)(jie)反(fan)時(shi),因電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的(de)濾波作用大(da)大(da)降低,一方面(mian)引起電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)輸(shu)(shu)出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓波動(dong),另一方面(mian)又因反(fan)向通電(dian)(dian)(dian)(dian)(dian)(dian)使(shi)此時(shi)相當于(yu)(yu)一個電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)發熱(re).當反(fan)向電(dian)(dian)(dian)(dian)(dian)(dian)壓超過某值時(shi),電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)的(de)反(fan)向漏電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)將變得很小,這樣通電(dian)(dian)(dian)(dian)(dian)(dian)工(gong)作不(bu)久,即(ji)可使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)因過熱(re)而炸裂(lie)損壞(huai).
2.加(jia)在電(dian)(dian)解電(dian)(dian)容兩端(duan)的電(dian)(dian)壓(ya)(ya)不能超過其(qi)允許工作電(dian)(dian)壓(ya)(ya),在設計實際電(dian)(dian)路時(shi)(shi)應根據具體(ti)情況留有一定的余量,在設計穩(wen)壓(ya)(ya)電(dian)(dian)源(yuan)的濾波電(dian)(dian)容時(shi)(shi),如果交(jiao)流電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)(ya)為(wei)220~時(shi)(shi)變壓(ya)(ya)器次級的整流電(dian)(dian)壓(ya)(ya)可(ke)達22V,此(ci)時(shi)(shi)選擇耐壓(ya)(ya)為(wei)25V的電(dian)(dian)解電(dian)(dian)容一般可(ke)以(yi)滿足要(yao)求(qiu).但是,假如交(jiao)流電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)(ya)波動很大且(qie)有可(ke)能上升到(dao)250V以(yi)上時(shi)(shi),好選擇耐壓(ya)(ya)30V以(yi)上的電(dian)(dian)解電(dian)(dian)容。
3,電(dian)解電(dian)容在(zai)電(dian)路中不應(ying)靠(kao)近大(da)功率(lv)發熱(re)(re)元件,以(yi)防(fang)因受熱(re)(re)而使電(dian)解液加速干涸.
4、對于有正負極(ji)性的信號(hao)的濾波,可(ke)采取兩個(ge)電(dian)(dian)解電(dian)(dian)容同極(ji)性串聯(lian)的方法(fa),當作(zuo)一個(ge)無極(ji)性的電(dian)(dian)容
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