【電(dian)阻(zu)的作用】電(dian)阻(zu)在電(dian)路中(zhong)有什么作用 電(dian)阻(zu)器有哪些分類

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(shi)一(yi)個限流元件,將電阻(zu)接在電路中后,電阻(zu)器(qi)的(de)(de)阻(zu)值(zhi)(zhi)是(shi)固定(ding)的(de)(de)一(yi)般是(shi)兩(liang)個引(yin)腳,它(ta)(ta)可(ke)限制通(tong)過它(ta)(ta)所連支路的(de)(de)電流大小?阻(zu)值(zhi)(zhi)不(bu)能改變(bian)(bian)的(de)(de)稱(cheng)為固定(ding)電阻(zu)器(qi)?阻(zu)值(zhi)(zhi)可(ke)變(bian)(bian)的(de)(de)稱(cheng)為電位器(qi)或可(ke)變(bian)(bian)電阻(zu)器(qi)?理想(xiang)的(de)(de)電阻(zu)器(qi)是(shi)線(xian)性的(de)(de),即通(tong)過電阻(zu)器(qi)的(de)(de)瞬時電流與(yu)外(wai)加瞬時電壓成(cheng)正比?用于(yu)分(fen)壓的(de)(de)可(ke)變(bian)(bian)電阻(zu)器(qi)?在裸露(lu)的(de)(de)電阻(zu)體上,緊壓著一(yi)至兩(liang)個可(ke)移金屬(shu)觸(chu)點?觸(chu)點位置確(que)定(ding)電阻(zu)體任一(yi)端(duan)與(yu)觸(chu)點間的(de)(de)阻(zu)值(zhi)(zhi)?

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小(xiao)功率(lv)(lv)電阻器通(tong)常為(wei)封裝在塑料外殼中(zhong)的碳(tan)膜構成,而大功率(lv)(lv)的電阻器通(tong)常為(wei)繞線(xian)電阻器,通(tong)過(guo)將大電阻率(lv)(lv)的金屬絲繞在瓷心上而制成?

如(ru)果(guo)一個(ge)電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)值接(jie)近零歐姆(mu),則該(gai)電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)對電(dian)(dian)(dian)流(liu)(liu)沒(mei)有阻(zu)(zu)礙作(zuo)用(yong),并聯這種電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)(de)回路(lu)(lu)被短路(lu)(lu),電(dian)(dian)(dian)流(liu)(liu)無(wu)限(xian)大(da)?如(ru)果(guo)一個(ge)電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)具(ju)有無(wu)限(xian)大(da)的(de)(de)(de)或(huo)很大(da)的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu),則串接(jie)該(gai)電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)(de)回路(lu)(lu)可看作(zuo)開路(lu)(lu),電(dian)(dian)(dian)流(liu)(liu)為(wei)零?工業中常用(yong)的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)介于兩種極端情(qing)況(kuang)之(zhi)間(jian),它具(ju)有一定(ding)(ding)的(de)(de)(de)電(dian)(dian)(dian)阻(zu)(zu),可通過一定(ding)(ding)的(de)(de)(de)電(dian)(dian)(dian)流(liu)(liu),但電(dian)(dian)(dian)流(liu)(liu)不像短路(lu)(lu)時那樣(yang)大(da)?電(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)(de)限(xian)流(liu)(liu)作(zuo)用(yong)類似于接(jie)在兩根大(da)直徑管子(zi)之(zhi)間(jian)的(de)(de)(de)小直徑管子(zi)限(xian)制水(shui)流(liu)(liu)量的(de)(de)(de)作(zuo)用(yong)?

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,其電阻幾乎維持(chi)不變而為(wei)(wei)一(yi)(yi)定(ding)值(zhi),這(zhe)類電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)稱為(wei)(wei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)?有些材料(liao)的(de)(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)明顯地隨著電(dian)(dian)(dian)流(liu)(或電(dian)(dian)(dian)壓)而變化,其伏—安(an)特性(xing)(xing)是一(yi)(yi)條曲線(xian)(xian),這(zhe)類電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)稱為(wei)(wei)非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)?非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)在(zai)某一(yi)(yi)給定(ding)的(de)(de)電(dian)(dian)(dian)壓(或電(dian)(dian)(dian)流(liu))作用下,電(dian)(dian)(dian)壓與(yu)電(dian)(dian)(dian)流(liu)的(de)(de)比值(zhi)為(wei)(wei)在(zai)該工(gong)作點(dian)下的(de)(de)靜(jing)態電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu),伏—安(an)特性(xing)(xing)曲線(xian)(xian)上的(de)(de)斜率為(wei)(wei)動態電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)?表達(da)非(fei)線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)特性(xing)(xing)的(de)(de)方式比較(jiao)復雜,但這(zhe)些非(fei)線(xian)(xian)性(xing)(xing)關系(xi)在(zai)電(dian)(dian)(dian)子電(dian)(dian)(dian)路中得到了廣泛的(de)(de)應用?

按材料分類

a?線(xian)繞(rao)電(dian)(dian)阻(zu)(zu)器(qi)由電(dian)(dian)阻(zu)(zu)線(xian)繞(rao)成電(dian)(dian)阻(zu)(zu)器(qi) 用高阻(zu)(zu)合金線(xian)繞(rao)在(zai)絕(jue)緣(yuan)骨架上制成,外面涂(tu)有(you)耐(nai)熱的釉絕(jue)緣(yuan)層或絕(jue)緣(yuan)漆?繞(rao)線(xian)電(dian)(dian)阻(zu)(zu)具有(you)較(jiao)低的溫度系數(shu),阻(zu)(zu)值精度高,穩定性(xing)好,耐(nai)熱耐(nai)腐蝕,主要做精密大功率電(dian)(dian)阻(zu)(zu)使用,缺(que)點是(shi)高頻性(xing)能差,時間(jian)常數(shu)大?

b?碳合成電阻(zu)器由碳及合成塑膠(jiao)壓制成而(er)成?

c?碳膜電阻器(qi)在瓷管上鍍上一層碳而成,將結晶碳沉積在陶瓷棒骨架上制成?碳膜電阻器(qi)成本(ben)低(di)?性(xing)能穩定(ding)?阻值范圍(wei)寬?溫(wen)度系(xi)數和電壓系(xi)數低(di),是目前(qian)應(ying)用最(zui)廣泛的電阻器(qi)?

d?金屬(shu)膜電阻(zu)器(qi)在(zai)瓷管上鍍上一層金屬(shu)而成(cheng),用(yong)真(zhen)空蒸發的方(fang)法將合金材料(liao)蒸鍍于陶(tao)瓷棒骨架表面?

金屬膜電阻比碳膜電阻的精度高,穩(wen)定性好,噪聲,溫度系(xi)數小(xiao)?在儀器儀表及通訊設備中大量(liang)采用?

e?金屬氧化膜電阻器在瓷管上鍍上一層(ceng)(ceng)氧(yang)化錫而成(cheng),在絕(jue)緣棒(bang)上沉積(ji)一層(ceng)(ceng)金屬氧(yang)化物?由于(yu)其(qi)本身即是氧(yang)化物,所(suo)以高(gao)溫下穩定(ding),耐熱沖擊,負載能力強(qiang) 按用途分(fen),有通用?精密?高(gao)頻?高(gao)壓?高(gao)阻?大功率和電阻網(wang)絡(luo)等?

特殊電阻器

1?保(bao)險(xian)電(dian)(dian)阻:又叫熔斷(duan)電(dian)(dian)阻器,在正常情況下起著電(dian)(dian)阻和(he)保(bao)險(xian)絲(si)的雙重作用,當電(dian)(dian)路出現故障而(er)使(shi)其功(gong)率(lv)(lv)超過(guo)額定功(gong)率(lv)(lv)時,它會(hui)像保(bao)險(xian)絲(si)一樣(yang)熔斷(duan)使(shi)連接(jie)電(dian)(dian)路斷(duan)開?保(bao)險(xian)絲(si)電(dian)(dian)阻一般電(dian)(dian)阻值(zhi)都小(xiao)(0.33Ω~10KΩ),功(gong)率(lv)(lv)也較小(xiao)?保(bao)險(xian)絲(si)電(dian)(dian)阻器常用型號(hao)有(you):RF10型?RF111-5保(bao)險(xian)絲(si)電(dian)(dian)阻器的符號(hao)型?RRD0910型?RRD0911型等(deng)?

2?敏(min)(min)(min)(min)感(gan)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器:是指其電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)值(zhi)對于某種物(wu)理(li)量(如溫度(du)?濕度(du)?光(guang)照(zhao)?電(dian)(dian)(dian)(dian)(dian)(dian)壓?機(ji)械(xie)力?以及(ji)氣體(ti)濃度(du)等)具有敏(min)(min)(min)(min)感(gan)特性,當這些(xie)物(wu)理(li)量發(fa)(fa)生(sheng)變化時,敏(min)(min)(min)(min)感(gan)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)(zu)值(zhi)就(jiu)會隨物(wu)理(li)量變化而發(fa)(fa)生(sheng)改(gai)變,呈現不(bu)同的(de)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)值(zhi)?根據(ju)對不(bu)同物(wu)理(li)量敏(min)(min)(min)(min)感(gan),敏(min)(min)(min)(min)感(gan)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器可分(fen)為熱敏(min)(min)(min)(min)?濕敏(min)(min)(min)(min)?光(guang)敏(min)(min)(min)(min)?壓敏(min)(min)(min)(min)?力敏(min)(min)(min)(min)?磁敏(min)(min)(min)(min)和(he)氣敏(min)(min)(min)(min)等類型敏(min)(min)(min)(min)感(gan)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)?敏(min)(min)(min)(min)感(gan)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器所用的(de)材(cai)(cai)料幾乎都是半導體(ti)材(cai)(cai)料,這類電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器也稱為半導體(ti)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器?

熱敏電阻的(de)(de)(de)阻(zu)值隨溫(wen)(wen)度(du)變化(hua)而(er)變化(hua),溫(wen)(wen)度(du)升高阻(zu)為(wei)負(fu)溫(wen)(wen)度(du)系(xi)(xi)數(shu)(shu)(NTC)熱(re)敏(min)電(dian)(dian)阻(zu)?應用(yong)較(jiao)多的(de)(de)(de)是負(fu)溫(wen)(wen)度(du)系(xi)(xi)數(shu)(shu)熱(re)敏(min)電(dian)(dian)阻(zu),又可分為(wei)普(pu)通型(xing)負(fu)溫(wen)(wen)度(du)系(xi)(xi)數(shu)(shu)熱(re)敏(min)電(dian)(dian)阻(zu);穩壓型(xing)負(fu)溫(wen)(wen)度(du)系(xi)(xi)數(shu)(shu)熱(re)敏(min)電(dian)(dian)阻(zu);測溫(wen)(wen)型(xing)負(fu)溫(wen)(wen)度(du)系(xi)(xi)數(shu)(shu)熱(re)敏(min)電(dian)(dian)阻(zu)等(deng)? 光(guang)(guang)敏(min)電(dian)(dian)阻(zu)是電(dian)(dian)阻(zu)的(de)(de)(de)阻(zu)值隨入射光(guang)(guang)的(de)(de)(de)強弱變化(hua)而(er)改變,當入射光(guang)(guang)增強時,光(guang)(guang)敏(min)電(dian)(dian)阻(zu)的(de)(de)(de)減(jian)小,入射光(guang)(guang)減(jian)弱時電(dian)(dian)阻(zu)值增大?