【電(dian)阻的作用】電(dian)阻在電(dian)路中(zhong)有(you)什(shen)么作用 電(dian)阻器有(you)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(yuan)件,將電(dian)(dian)(dian)阻(zu)接在(zai)電(dian)(dian)(dian)路(lu)中后,電(dian)(dian)(dian)阻(zu)器的(de)(de)(de)(de)阻(zu)值是(shi)固定的(de)(de)(de)(de)一(yi)般是(shi)兩個引腳,它(ta)可(ke)(ke)限制(zhi)通(tong)過(guo)它(ta)所(suo)連支路(lu)的(de)(de)(de)(de)電(dian)(dian)(dian)流大小?阻(zu)值不能(neng)改變的(de)(de)(de)(de)稱為(wei)(wei)固定電(dian)(dian)(dian)阻(zu)器?阻(zu)值可(ke)(ke)變的(de)(de)(de)(de)稱為(wei)(wei)電(dian)(dian)(dian)位器或(huo)可(ke)(ke)變電(dian)(dian)(dian)阻(zu)器?理想的(de)(de)(de)(de)電(dian)(dian)(dian)阻(zu)器是(shi)線性的(de)(de)(de)(de),即(ji)通(tong)過(guo)電(dian)(dian)(dian)阻(zu)器的(de)(de)(de)(de)瞬時電(dian)(dian)(dian)流與(yu)外加瞬時電(dian)(dian)(dian)壓(ya)成(cheng)正比?用于分壓(ya)的(de)(de)(de)(de)可(ke)(ke)變電(dian)(dian)(dian)阻(zu)器?在(zai)裸露的(de)(de)(de)(de)電(dian)(dian)(dian)阻(zu)體上,緊(jin)壓(ya)著(zhu)一(yi)至(zhi)兩個可(ke)(ke)移(yi)金屬觸點(dian)?觸點(dian)位置確(que)定電(dian)(dian)(dian)阻(zu)體任一(yi)端與(yu)觸點(dian)間的(de)(de)(de)(de)阻(zu)值?

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小功率電(dian)(dian)阻(zu)器通常為(wei)封(feng)裝(zhuang)在(zai)(zai)塑(su)料外殼中的(de)碳(tan)膜構成,而大功率的(de)電(dian)(dian)阻(zu)器通常為(wei)繞(rao)(rao)線電(dian)(dian)阻(zu)器,通過(guo)將大電(dian)(dian)阻(zu)率的(de)金屬絲繞(rao)(rao)在(zai)(zai)瓷心上而制成?

如(ru)果一(yi)個電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)接(jie)近零(ling)歐(ou)姆,則(ze)該電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)對電(dian)(dian)(dian)(dian)流沒有阻(zu)(zu)(zu)礙作(zuo)用,并聯這(zhe)種電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)回(hui)路(lu)(lu)(lu)被短(duan)路(lu)(lu)(lu),電(dian)(dian)(dian)(dian)流無限大(da)(da)(da)?如(ru)果一(yi)個電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)具有無限大(da)(da)(da)的(de)(de)或很大(da)(da)(da)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu),則(ze)串接(jie)該電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)回(hui)路(lu)(lu)(lu)可看(kan)作(zuo)開路(lu)(lu)(lu),電(dian)(dian)(dian)(dian)流為零(ling)?工(gong)業中常用的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)介于兩種極端(duan)情(qing)況(kuang)之間,它具有一(yi)定(ding)(ding)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu),可通過一(yi)定(ding)(ding)的(de)(de)電(dian)(dian)(dian)(dian)流,但電(dian)(dian)(dian)(dian)流不像短(duan)路(lu)(lu)(lu)時那樣大(da)(da)(da)?電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)的(de)(de)限流作(zuo)用類似于接(jie)在(zai)兩根(gen)大(da)(da)(da)直(zhi)徑管(guan)子之間的(de)(de)小直(zhi)徑管(guan)子限制水流量的(de)(de)作(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(hu)維持(chi)不變而為(wei)一定值(zhi),這(zhe)類(lei)電(dian)(dian)阻(zu)(zu)(zu)稱(cheng)(cheng)為(wei)線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)?有些材料的電(dian)(dian)阻(zu)(zu)(zu)明顯(xian)地隨著電(dian)(dian)流(liu)(或電(dian)(dian)壓)而變化,其伏—安特(te)性(xing)(xing)是一條曲線(xian),這(zhe)類(lei)電(dian)(dian)阻(zu)(zu)(zu)稱(cheng)(cheng)為(wei)非線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)?非線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)在某一給定的電(dian)(dian)壓(或電(dian)(dian)流(liu))作用下,電(dian)(dian)壓與(yu)電(dian)(dian)流(liu)的比值(zhi)為(wei)在該工(gong)作點下的靜態電(dian)(dian)阻(zu)(zu)(zu),伏—安特(te)性(xing)(xing)曲線(xian)上的斜率為(wei)動態電(dian)(dian)阻(zu)(zu)(zu)?表達非線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)特(te)性(xing)(xing)的方式(shi)比較復雜,但(dan)這(zhe)些非線(xian)性(xing)(xing)關系在電(dian)(dian)子電(dian)(dian)路中得(de)到了廣(guang)泛的應(ying)用?

按材料分類

a?線繞(rao)電(dian)阻器由(you)電(dian)阻線繞(rao)成電(dian)阻器 用高(gao)阻合(he)金線繞(rao)在絕緣骨架上制成,外面涂有耐(nai)熱(re)(re)的(de)釉絕緣層或絕緣漆?繞(rao)線電(dian)阻具(ju)有較低的(de)溫度系數,阻值精度高(gao),穩定性(xing)好(hao),耐(nai)熱(re)(re)耐(nai)腐蝕,主要做精密大(da)功率電(dian)阻使用,缺點是高(gao)頻性(xing)能(neng)差,時間常數大(da)?

b?碳(tan)合成(cheng)(cheng)(cheng)電阻器由碳(tan)及合成(cheng)(cheng)(cheng)塑膠壓制成(cheng)(cheng)(cheng)而成(cheng)(cheng)(cheng)?

c?碳膜電阻器(qi)在(zai)(zai)瓷管上鍍上一層碳而成(cheng)(cheng),將結晶碳沉積在(zai)(zai)陶瓷棒骨(gu)架(jia)上制成(cheng)(cheng)?碳膜電阻器(qi)成(cheng)(cheng)本低?性能(neng)穩(wen)定?阻值范圍寬?溫(wen)度系數和電壓系數低,是目前應用最廣泛的電阻器(qi)?

d?金(jin)屬膜電阻器在瓷管上鍍上一(yi)層金(jin)屬而成,用真空(kong)蒸發的方(fang)法將合金(jin)材料蒸鍍于陶瓷棒骨架表面?

金屬膜電阻比碳膜電阻的精(jing)度(du)高,穩定性好,噪聲,溫度(du)系數(shu)小?在儀器儀表及通訊設備中大量采用?

e?金屬氧化膜電阻器在瓷管上(shang)鍍上(shang)一層氧化錫而成,在絕緣棒上(shang)沉積(ji)一層金(jin)屬氧化物?由于(yu)其本身即是(shi)氧化物,所以高溫下(xia)穩定,耐熱沖擊,負載能力強 按用途(tu)分,有通(tong)用?精密?高頻?高壓?高阻(zu)?大功率和(he)電阻(zu)網絡等?

特殊電阻器

1?保(bao)(bao)險(xian)(xian)(xian)電(dian)(dian)阻:又叫熔(rong)斷電(dian)(dian)阻器(qi),在正常(chang)情(qing)況下起著電(dian)(dian)阻和保(bao)(bao)險(xian)(xian)(xian)絲(si)(si)(si)的雙重作用(yong),當電(dian)(dian)路出現故障而使其功(gong)率超過額定功(gong)率時,它會像保(bao)(bao)險(xian)(xian)(xian)絲(si)(si)(si)一樣熔(rong)斷使連接電(dian)(dian)路斷開?保(bao)(bao)險(xian)(xian)(xian)絲(si)(si)(si)電(dian)(dian)阻一般電(dian)(dian)阻值都小(xiao)(0.33Ω~10KΩ),功(gong)率也較小(xiao)?保(bao)(bao)險(xian)(xian)(xian)絲(si)(si)(si)電(dian)(dian)阻器(qi)常(chang)用(yong)型號有:RF10型?RF111-5保(bao)(bao)險(xian)(xian)(xian)絲(si)(si)(si)電(dian)(dian)阻器(qi)的符號型?RRD0910型?RRD0911型等?

2?敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)(zu)器(qi):是指其電(dian)(dian)阻(zu)(zu)(zu)值對于(yu)某種物理(li)量(liang)(如溫(wen)度?濕度?光照?電(dian)(dian)壓?機械力(li)?以及氣(qi)(qi)體(ti)濃度等)具(ju)有敏(min)(min)感(gan)特性(xing),當這些物理(li)量(liang)發(fa)生變(bian)化時,敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)值就會(hui)隨物理(li)量(liang)變(bian)化而(er)發(fa)生改(gai)變(bian),呈現不同的(de)電(dian)(dian)阻(zu)(zu)(zu)值?根(gen)據(ju)對不同物理(li)量(liang)敏(min)(min)感(gan),敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)(zu)器(qi)可分為(wei)熱敏(min)(min)?濕敏(min)(min)?光敏(min)(min)?壓敏(min)(min)?力(li)敏(min)(min)?磁敏(min)(min)和(he)氣(qi)(qi)敏(min)(min)等類型(xing)敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)(zu)?敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)(zu)器(qi)所用的(de)材料(liao)幾乎都(dou)是半導(dao)體(ti)材料(liao),這類電(dian)(dian)阻(zu)(zu)(zu)器(qi)也(ye)稱為(wei)半導(dao)體(ti)電(dian)(dian)阻(zu)(zu)(zu)器(qi)?

熱敏電阻的(de)(de)阻(zu)(zu)(zu)值(zhi)隨(sui)溫(wen)度(du)(du)變化而變化,溫(wen)度(du)(du)升(sheng)高阻(zu)(zu)(zu)為負(fu)溫(wen)度(du)(du)系(xi)(xi)數(NTC)熱(re)(re)(re)敏(min)電(dian)(dian)阻(zu)(zu)(zu)?應用(yong)較多(duo)的(de)(de)是負(fu)溫(wen)度(du)(du)系(xi)(xi)數熱(re)(re)(re)敏(min)電(dian)(dian)阻(zu)(zu)(zu),又可分(fen)為普通型(xing)負(fu)溫(wen)度(du)(du)系(xi)(xi)數熱(re)(re)(re)敏(min)電(dian)(dian)阻(zu)(zu)(zu);穩壓(ya)型(xing)負(fu)溫(wen)度(du)(du)系(xi)(xi)數熱(re)(re)(re)敏(min)電(dian)(dian)阻(zu)(zu)(zu);測溫(wen)型(xing)負(fu)溫(wen)度(du)(du)系(xi)(xi)數熱(re)(re)(re)敏(min)電(dian)(dian)阻(zu)(zu)(zu)等? 光敏(min)電(dian)(dian)阻(zu)(zu)(zu)是電(dian)(dian)阻(zu)(zu)(zu)的(de)(de)阻(zu)(zu)(zu)值(zhi)隨(sui)入射(she)光的(de)(de)強弱變化而改變,當入射(she)光增(zeng)強時,光敏(min)電(dian)(dian)阻(zu)(zu)(zu)的(de)(de)減小,入射(she)光減弱時電(dian)(dian)阻(zu)(zu)(zu)值(zhi)增(zeng)大?