【電(dian)阻的作用】電(dian)阻在(zai)電(dian)路中有(you)什么作用 電(dian)阻器有(you)哪些分(fen)類

電阻在電路中有什么作用

電阻器在日常生活中一般直接稱為電阻?是一(yi)個限流(liu)元件,將電(dian)(dian)(dian)阻(zu)(zu)(zu)接在電(dian)(dian)(dian)路(lu)中(zhong)后(hou),電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)(de)阻(zu)(zu)(zu)值(zhi)是固定的(de)(de)(de)一(yi)般(ban)是兩個引腳(jiao),它可(ke)(ke)限制通過(guo)它所(suo)連支路(lu)的(de)(de)(de)電(dian)(dian)(dian)流(liu)大小?阻(zu)(zu)(zu)值(zhi)不能改變的(de)(de)(de)稱(cheng)為(wei)固定電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)?阻(zu)(zu)(zu)值(zhi)可(ke)(ke)變的(de)(de)(de)稱(cheng)為(wei)電(dian)(dian)(dian)位(wei)器(qi)或可(ke)(ke)變電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)?理(li)想的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)是線性(xing)的(de)(de)(de),即(ji)通過(guo)電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)(de)瞬(shun)(shun)時電(dian)(dian)(dian)流(liu)與外(wai)加瞬(shun)(shun)時電(dian)(dian)(dian)壓成正比?用于分(fen)壓的(de)(de)(de)可(ke)(ke)變電(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)?在裸(luo)露的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)體上,緊壓著一(yi)至兩個可(ke)(ke)移(yi)金屬觸(chu)(chu)點?觸(chu)(chu)點位(wei)置確(que)定電(dian)(dian)(dian)阻(zu)(zu)(zu)體任一(yi)端與觸(chu)(chu)點間的(de)(de)(de)阻(zu)(zu)(zu)值(zhi)?

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小功(gong)率(lv)電(dian)(dian)阻(zu)器通常為封裝在塑料外殼中(zhong)的碳膜構成,而大功(gong)率(lv)的電(dian)(dian)阻(zu)器通常為繞線電(dian)(dian)阻(zu)器,通過將大電(dian)(dian)阻(zu)率(lv)的金屬絲繞在瓷心上而制成?

如(ru)果(guo)一個電(dian)(dian)(dian)阻(zu)(zu)器的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)值(zhi)接(jie)(jie)近零歐姆,則該電(dian)(dian)(dian)阻(zu)(zu)器對電(dian)(dian)(dian)流沒有(you)阻(zu)(zu)礙作(zuo)(zuo)用,并(bing)聯這種電(dian)(dian)(dian)阻(zu)(zu)器的(de)(de)(de)回(hui)(hui)路(lu)被短路(lu),電(dian)(dian)(dian)流無限(xian)大(da)?如(ru)果(guo)一個電(dian)(dian)(dian)阻(zu)(zu)器具有(you)無限(xian)大(da)的(de)(de)(de)或很(hen)大(da)的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu),則串接(jie)(jie)該電(dian)(dian)(dian)阻(zu)(zu)器的(de)(de)(de)回(hui)(hui)路(lu)可看作(zuo)(zuo)開路(lu),電(dian)(dian)(dian)流為(wei)零?工(gong)業中常用的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)器介于兩種極端情況之間,它(ta)具有(you)一定的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu),可通過(guo)一定的(de)(de)(de)電(dian)(dian)(dian)流,但電(dian)(dian)(dian)流不像短路(lu)時(shi)那樣大(da)?電(dian)(dian)(dian)阻(zu)(zu)器的(de)(de)(de)限(xian)流作(zuo)(zuo)用類似(si)于接(jie)(jie)在兩根大(da)直徑管子之間的(de)(de)(de)小直徑管子限(xian)制水流量的(de)(de)(de)作(zuo)(zuo)用?

電阻器有哪些分類

按伏安特性分類

對大多數導體來說,在一定的溫度下,其電阻幾乎維(wei)持(chi)不變而為(wei)一(yi)定值,這類(lei)(lei)電(dian)(dian)(dian)阻(zu)稱為(wei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)?有些(xie)材料(liao)的(de)電(dian)(dian)(dian)阻(zu)明顯地隨著電(dian)(dian)(dian)流(liu)(liu)(或電(dian)(dian)(dian)壓)而變化,其伏—安特(te)性(xing)(xing)是一(yi)條曲線(xian)(xian),這類(lei)(lei)電(dian)(dian)(dian)阻(zu)稱為(wei)非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)?非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)在(zai)某一(yi)給定的(de)電(dian)(dian)(dian)壓(或電(dian)(dian)(dian)流(liu)(liu))作用下,電(dian)(dian)(dian)壓與電(dian)(dian)(dian)流(liu)(liu)的(de)比值為(wei)在(zai)該工作點下的(de)靜態電(dian)(dian)(dian)阻(zu),伏—安特(te)性(xing)(xing)曲線(xian)(xian)上的(de)斜率為(wei)動態電(dian)(dian)(dian)阻(zu)?表達非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)特(te)性(xing)(xing)的(de)方(fang)式(shi)比較復(fu)雜,但這些(xie)非(fei)線(xian)(xian)性(xing)(xing)關系在(zai)電(dian)(dian)(dian)子電(dian)(dian)(dian)路中得到了廣(guang)泛的(de)應(ying)用?

按材料分類

a?線繞電阻(zu)器由電阻(zu)線繞成電阻(zu)器 用(yong)(yong)高(gao)阻(zu)合金線繞在絕(jue)(jue)緣(yuan)(yuan)骨架上(shang)制成,外面涂有耐(nai)(nai)熱(re)的釉絕(jue)(jue)緣(yuan)(yuan)層或絕(jue)(jue)緣(yuan)(yuan)漆?繞線電阻(zu)具有較(jiao)低的溫度系(xi)數(shu),阻(zu)值精(jing)度高(gao),穩定性好,耐(nai)(nai)熱(re)耐(nai)(nai)腐蝕,主要做精(jing)密大功(gong)率電阻(zu)使用(yong)(yong),缺點是(shi)高(gao)頻性能差,時間(jian)常數(shu)大?

b?碳合成(cheng)(cheng)電阻器由碳及合成(cheng)(cheng)塑膠壓(ya)制成(cheng)(cheng)而(er)成(cheng)(cheng)?

c?碳(tan)膜(mo)電(dian)(dian)阻(zu)器在瓷管上鍍上一層碳(tan)而成,將(jiang)結(jie)晶碳(tan)沉(chen)積(ji)在陶瓷棒骨架上制成?碳(tan)膜(mo)電(dian)(dian)阻(zu)器成本低?性能穩定?阻(zu)值范圍寬?溫度系數和(he)電(dian)(dian)壓系數低,是目前(qian)應用(yong)最廣(guang)泛的電(dian)(dian)阻(zu)器?

d?金屬(shu)膜電阻器在瓷(ci)(ci)管上鍍上一層金屬(shu)而成(cheng),用(yong)真空蒸發的方法(fa)將合金材料蒸鍍于陶瓷(ci)(ci)棒骨架表(biao)面?

金屬膜(mo)電阻比碳膜(mo)電阻的精度(du)高,穩(wen)定性好(hao),噪聲,溫度(du)系(xi)數小(xiao)?在儀器儀表及通訊(xun)設備中大量(liang)采用?

e?金屬氧化膜電阻器在(zai)瓷管(guan)上(shang)鍍上(shang)一層氧(yang)(yang)化(hua)(hua)錫而(er)成,在(zai)絕緣棒上(shang)沉(chen)積一層金屬氧(yang)(yang)化(hua)(hua)物(wu)(wu)?由于其本身(shen)即是氧(yang)(yang)化(hua)(hua)物(wu)(wu),所以高(gao)溫下穩定(ding),耐熱沖擊,負載能(neng)力強 按用途分,有(you)通用?精密?高(gao)頻?高(gao)壓?高(gao)阻(zu)?大功率和電阻(zu)網絡等?

特殊電阻器

1?保(bao)(bao)險(xian)電(dian)阻:又叫(jiao)熔(rong)斷(duan)電(dian)阻器,在正常情況下(xia)起著電(dian)阻和保(bao)(bao)險(xian)絲(si)的雙重作用(yong),當電(dian)路出現故障而使(shi)其(qi)功(gong)率超過額定(ding)功(gong)率時,它(ta)會像保(bao)(bao)險(xian)絲(si)一(yi)樣熔(rong)斷(duan)使(shi)連接電(dian)路斷(duan)開?保(bao)(bao)險(xian)絲(si)電(dian)阻一(yi)般電(dian)阻值(zhi)都小(xiao)(0.33Ω~10KΩ),功(gong)率也較小(xiao)?保(bao)(bao)險(xian)絲(si)電(dian)阻器常用(yong)型號(hao)有:RF10型?RF111-5保(bao)(bao)險(xian)絲(si)電(dian)阻器的符號(hao)型?RRD0910型?RRD0911型等?

2?敏(min)(min)感(gan)(gan)電(dian)(dian)(dian)阻(zu)(zu)器:是指(zhi)其電(dian)(dian)(dian)阻(zu)(zu)值對于某種物(wu)理量(如(ru)溫(wen)度?濕度?光照?電(dian)(dian)(dian)壓?機械(xie)力?以及氣體(ti)濃度等(deng))具有敏(min)(min)感(gan)(gan)特性,當(dang)這些物(wu)理量發生變(bian)化(hua)時(shi),敏(min)(min)感(gan)(gan)電(dian)(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值就會隨物(wu)理量變(bian)化(hua)而(er)發生改變(bian),呈現不同的(de)電(dian)(dian)(dian)阻(zu)(zu)值?根據對不同物(wu)理量敏(min)(min)感(gan)(gan),敏(min)(min)感(gan)(gan)電(dian)(dian)(dian)阻(zu)(zu)器可分(fen)為熱敏(min)(min)?濕敏(min)(min)?光敏(min)(min)?壓敏(min)(min)?力敏(min)(min)?磁敏(min)(min)和氣敏(min)(min)等(deng)類型敏(min)(min)感(gan)(gan)電(dian)(dian)(dian)阻(zu)(zu)?敏(min)(min)感(gan)(gan)電(dian)(dian)(dian)阻(zu)(zu)器所用的(de)材(cai)料(liao)幾(ji)乎(hu)都是半(ban)導體(ti)材(cai)料(liao),這類電(dian)(dian)(dian)阻(zu)(zu)器也稱為半(ban)導體(ti)電(dian)(dian)(dian)阻(zu)(zu)器?

熱敏電阻的(de)(de)阻(zu)(zu)值隨溫(wen)(wen)(wen)度(du)(du)變(bian)化而變(bian)化,溫(wen)(wen)(wen)度(du)(du)升高阻(zu)(zu)為負(fu)(fu)溫(wen)(wen)(wen)度(du)(du)系數(shu)(shu)(shu)(NTC)熱(re)(re)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu)?應用較多的(de)(de)是負(fu)(fu)溫(wen)(wen)(wen)度(du)(du)系數(shu)(shu)(shu)熱(re)(re)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu),又(you)可分為普通型(xing)負(fu)(fu)溫(wen)(wen)(wen)度(du)(du)系數(shu)(shu)(shu)熱(re)(re)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu);穩壓(ya)型(xing)負(fu)(fu)溫(wen)(wen)(wen)度(du)(du)系數(shu)(shu)(shu)熱(re)(re)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu);測溫(wen)(wen)(wen)型(xing)負(fu)(fu)溫(wen)(wen)(wen)度(du)(du)系數(shu)(shu)(shu)熱(re)(re)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu)等? 光(guang)(guang)(guang)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu)是電(dian)(dian)(dian)阻(zu)(zu)的(de)(de)阻(zu)(zu)值隨入射(she)光(guang)(guang)(guang)的(de)(de)強弱(ruo)變(bian)化而改變(bian),當入射(she)光(guang)(guang)(guang)增強時(shi),光(guang)(guang)(guang)敏(min)(min)電(dian)(dian)(dian)阻(zu)(zu)的(de)(de)減小,入射(she)光(guang)(guang)(guang)減弱(ruo)時(shi)電(dian)(dian)(dian)阻(zu)(zu)值增大?