【電阻的(de)作用(yong)】電阻在電路(lu)中有(you)什么作用(yong) 電阻器有(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?是一個(ge)限流(liu)元(yuan)件,將電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)接在(zai)電(dian)(dian)(dian)路(lu)中后,電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)的(de)阻(zu)(zu)(zu)(zu)(zu)值是固(gu)定(ding)的(de)一般是兩個(ge)引腳,它可(ke)(ke)(ke)限制(zhi)通過它所連支路(lu)的(de)電(dian)(dian)(dian)流(liu)大小?阻(zu)(zu)(zu)(zu)(zu)值不(bu)能改變(bian)(bian)的(de)稱為(wei)固(gu)定(ding)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)?阻(zu)(zu)(zu)(zu)(zu)值可(ke)(ke)(ke)變(bian)(bian)的(de)稱為(wei)電(dian)(dian)(dian)位器(qi)或可(ke)(ke)(ke)變(bian)(bian)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)?理想的(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)是線性的(de),即(ji)通過電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)的(de)瞬時(shi)電(dian)(dian)(dian)流(liu)與外加瞬時(shi)電(dian)(dian)(dian)壓(ya)成正比?用于(yu)分壓(ya)的(de)可(ke)(ke)(ke)變(bian)(bian)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)?在(zai)裸露的(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)體(ti)上,緊壓(ya)著一至(zhi)兩個(ge)可(ke)(ke)(ke)移金(jin)屬觸點?觸點位置確定(ding)電(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)體(ti)任一端與觸點間的(de)阻(zu)(zu)(zu)(zu)(zu)值?

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小(xiao)功率電(dian)阻器通(tong)常(chang)為(wei)封裝(zhuang)在(zai)塑料外殼中的碳(tan)膜(mo)構(gou)成(cheng)(cheng),而大功率的電(dian)阻器通(tong)常(chang)為(wei)繞線電(dian)阻器,通(tong)過將大電(dian)阻率的金屬(shu)絲繞在(zai)瓷心上而制成(cheng)(cheng)?

如(ru)果一個電(dian)阻(zu)(zu)(zu)器的(de)(de)(de)電(dian)阻(zu)(zu)(zu)值接近(jin)零歐姆(mu),則(ze)該電(dian)阻(zu)(zu)(zu)器對電(dian)流(liu)(liu)(liu)(liu)沒(mei)有(you)阻(zu)(zu)(zu)礙作(zuo)用,并聯這種(zhong)(zhong)電(dian)阻(zu)(zu)(zu)器的(de)(de)(de)回(hui)路(lu)(lu)(lu)被短路(lu)(lu)(lu),電(dian)流(liu)(liu)(liu)(liu)無限大(da)?如(ru)果一個電(dian)阻(zu)(zu)(zu)器具(ju)(ju)有(you)無限大(da)的(de)(de)(de)或很大(da)的(de)(de)(de)電(dian)阻(zu)(zu)(zu),則(ze)串接該電(dian)阻(zu)(zu)(zu)器的(de)(de)(de)回(hui)路(lu)(lu)(lu)可(ke)看作(zuo)開路(lu)(lu)(lu),電(dian)流(liu)(liu)(liu)(liu)為零?工業中常用的(de)(de)(de)電(dian)阻(zu)(zu)(zu)器介于兩種(zhong)(zhong)極端情況之間,它具(ju)(ju)有(you)一定的(de)(de)(de)電(dian)阻(zu)(zu)(zu),可(ke)通過一定的(de)(de)(de)電(dian)流(liu)(liu)(liu)(liu),但電(dian)流(liu)(liu)(liu)(liu)不像短路(lu)(lu)(lu)時那樣大(da)?電(dian)阻(zu)(zu)(zu)器的(de)(de)(de)限流(liu)(liu)(liu)(liu)作(zuo)用類似(si)于接在兩根大(da)直徑管子之間的(de)(de)(de)小直徑管子限制(zhi)水(shui)流(liu)(liu)(liu)(liu)量(liang)的(de)(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,其電阻幾乎維(wei)持(chi)不(bu)變(bian)而(er)為(wei)(wei)一(yi)(yi)定值,這(zhe)類電(dian)(dian)阻(zu)(zu)(zu)(zu)稱為(wei)(wei)線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)(zu)?有些材料的(de)(de)(de)電(dian)(dian)阻(zu)(zu)(zu)(zu)明顯地隨著(zhu)電(dian)(dian)流(liu)(或電(dian)(dian)壓(ya))而(er)變(bian)化,其伏—安特性(xing)(xing)是一(yi)(yi)條曲(qu)(qu)線(xian),這(zhe)類電(dian)(dian)阻(zu)(zu)(zu)(zu)稱為(wei)(wei)非(fei)線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)(zu)?非(fei)線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)(zu)在(zai)某一(yi)(yi)給定的(de)(de)(de)電(dian)(dian)壓(ya)(或電(dian)(dian)流(liu))作用下(xia),電(dian)(dian)壓(ya)與電(dian)(dian)流(liu)的(de)(de)(de)比(bi)(bi)值為(wei)(wei)在(zai)該工作點(dian)下(xia)的(de)(de)(de)靜(jing)態電(dian)(dian)阻(zu)(zu)(zu)(zu),伏—安特性(xing)(xing)曲(qu)(qu)線(xian)上的(de)(de)(de)斜率(lv)為(wei)(wei)動(dong)態電(dian)(dian)阻(zu)(zu)(zu)(zu)?表達非(fei)線(xian)性(xing)(xing)電(dian)(dian)阻(zu)(zu)(zu)(zu)特性(xing)(xing)的(de)(de)(de)方式比(bi)(bi)較(jiao)復雜(za),但(dan)這(zhe)些非(fei)線(xian)性(xing)(xing)關系在(zai)電(dian)(dian)子(zi)電(dian)(dian)路中得到了廣泛的(de)(de)(de)應用?

按材料分類

a?線(xian)(xian)(xian)繞(rao)電(dian)(dian)(dian)阻器(qi)由電(dian)(dian)(dian)阻線(xian)(xian)(xian)繞(rao)成(cheng)電(dian)(dian)(dian)阻器(qi) 用(yong)高阻合(he)金線(xian)(xian)(xian)繞(rao)在(zai)絕緣骨架上制成(cheng),外(wai)面涂有耐(nai)熱的釉絕緣層或絕緣漆?繞(rao)線(xian)(xian)(xian)電(dian)(dian)(dian)阻具有較(jiao)低的溫度系(xi)數(shu),阻值(zhi)精度高,穩(wen)定(ding)性(xing)好,耐(nai)熱耐(nai)腐蝕(shi),主要做(zuo)精密大(da)功率電(dian)(dian)(dian)阻使用(yong),缺點(dian)是高頻性(xing)能差(cha),時間常數(shu)大(da)?

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

c?碳膜電(dian)阻(zu)器在瓷(ci)管上(shang)鍍上(shang)一層碳而成,將結晶(jing)碳沉積在陶瓷(ci)棒骨架上(shang)制(zhi)成?碳膜電(dian)阻(zu)器成本低?性能穩定?阻(zu)值范圍寬?溫(wen)度(du)系數和電(dian)壓系數低,是目前應用(yong)最(zui)廣泛(fan)的(de)電(dian)阻(zu)器?

d?金(jin)屬膜電阻器在瓷(ci)管上(shang)鍍(du)上(shang)一層金(jin)屬而成,用真空(kong)蒸發的方法將合金(jin)材料蒸鍍(du)于陶瓷(ci)棒骨架表面(mian)?

金屬膜(mo)電(dian)阻比碳膜(mo)電(dian)阻的精度(du)高,穩定性好,噪聲,溫度(du)系數小?在儀(yi)器儀(yi)表及通訊設備中大量采用?

e?金屬氧化膜電阻器在(zai)瓷管上(shang)鍍上(shang)一(yi)層氧(yang)化(hua)(hua)錫而(er)成(cheng),在(zai)絕緣棒上(shang)沉積一(yi)層金屬氧(yang)化(hua)(hua)物?由(you)于其(qi)本身即是氧(yang)化(hua)(hua)物,所(suo)以高溫下穩定,耐熱沖擊,負載能力強(qiang) 按用途分,有通用?精密?高頻?高壓?高阻(zu)?大(da)功率和電阻(zu)網(wang)絡(luo)等?

特殊電阻器

1?保(bao)(bao)險(xian)(xian)電(dian)阻:又叫熔(rong)斷電(dian)阻器,在正(zheng)常情況下起著電(dian)阻和保(bao)(bao)險(xian)(xian)絲的雙重作用,當(dang)電(dian)路出現(xian)故障(zhang)而使其功(gong)率(lv)超(chao)過額(e)定功(gong)率(lv)時,它會像保(bao)(bao)險(xian)(xian)絲一樣熔(rong)斷使連接電(dian)路斷開?保(bao)(bao)險(xian)(xian)絲電(dian)阻一般電(dian)阻值都(dou)小(xiao)(0.33Ω~10KΩ),功(gong)率(lv)也較小(xiao)?保(bao)(bao)險(xian)(xian)絲電(dian)阻器常用型(xing)號(hao)有:RF10型(xing)?RF111-5保(bao)(bao)險(xian)(xian)絲電(dian)阻器的符號(hao)型(xing)?RRD0910型(xing)?RRD0911型(xing)等?

2?敏(min)(min)感(gan)電(dian)(dian)阻(zu)器(qi):是指其電(dian)(dian)阻(zu)值(zhi)對(dui)(dui)于某種(zhong)物理(li)量(如溫度?濕(shi)(shi)度?光照?電(dian)(dian)壓?機械力(li)?以(yi)及氣體濃度等)具有敏(min)(min)感(gan)特性,當這些(xie)物理(li)量發(fa)生變化時,敏(min)(min)感(gan)電(dian)(dian)阻(zu)的阻(zu)值(zhi)就會隨(sui)物理(li)量變化而發(fa)生改(gai)變,呈(cheng)現(xian)不同的電(dian)(dian)阻(zu)值(zhi)?根據對(dui)(dui)不同物理(li)量敏(min)(min)感(gan),敏(min)(min)感(gan)電(dian)(dian)阻(zu)器(qi)可分為熱敏(min)(min)?濕(shi)(shi)敏(min)(min)?光敏(min)(min)?壓敏(min)(min)?力(li)敏(min)(min)?磁敏(min)(min)和氣敏(min)(min)等類型敏(min)(min)感(gan)電(dian)(dian)阻(zu)?敏(min)(min)感(gan)電(dian)(dian)阻(zu)器(qi)所用的材料幾乎都是半(ban)導體材料,這類電(dian)(dian)阻(zu)器(qi)也(ye)稱(cheng)為半(ban)導體電(dian)(dian)阻(zu)器(qi)?

熱敏電阻的阻(zu)值(zhi)隨溫(wen)(wen)度變(bian)化(hua)(hua)而變(bian)化(hua)(hua),溫(wen)(wen)度升(sheng)高(gao)阻(zu)為負(fu)溫(wen)(wen)度系數(shu)(NTC)熱(re)(re)敏(min)電(dian)阻(zu)?應用較多的是(shi)負(fu)溫(wen)(wen)度系數(shu)熱(re)(re)敏(min)電(dian)阻(zu),又可(ke)分為普通型(xing)(xing)負(fu)溫(wen)(wen)度系數(shu)熱(re)(re)敏(min)電(dian)阻(zu);穩壓型(xing)(xing)負(fu)溫(wen)(wen)度系數(shu)熱(re)(re)敏(min)電(dian)阻(zu);測溫(wen)(wen)型(xing)(xing)負(fu)溫(wen)(wen)度系數(shu)熱(re)(re)敏(min)電(dian)阻(zu)等? 光(guang)(guang)(guang)敏(min)電(dian)阻(zu)是(shi)電(dian)阻(zu)的阻(zu)值(zhi)隨入射光(guang)(guang)(guang)的強弱變(bian)化(hua)(hua)而改變(bian),當入射光(guang)(guang)(guang)增強時,光(guang)(guang)(guang)敏(min)電(dian)阻(zu)的減小,入射光(guang)(guang)(guang)減弱時電(dian)阻(zu)值(zhi)增大?