一、電阻的種類有哪些

1、按伏安特性分類

可分(fen)為(wei)(wei)(wei)線性電阻和非線性電阻。對大多數導體來(lai)說，在一(yi)定的溫度下，其電阻幾(ji)乎維持不變(bian)而(er)為(wei)(wei)(wei)一(yi)定值，這類(lei)電阻稱為(wei)(wei)(wei)線性電阻。

有些材料的(de)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)明顯地隨著電(dian)(dian)(dian)(dian)(dian)(dian)流（或(huo)電(dian)(dian)(dian)(dian)(dian)(dian)壓）而變(bian)化，其伏安特(te)性(xing)是(shi)一條曲線(xian)，這類(lei)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)稱為(wei)(wei)非(fei)線(xian)性(xing)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。非(fei)線(xian)性(xing)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)在(zai)某一給定的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓（或(huo)電(dian)(dian)(dian)(dian)(dian)(dian)流）作(zuo)用下(xia)，電(dian)(dian)(dian)(dian)(dian)(dian)壓與電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)比(bi)值為(wei)(wei)在(zai)該工(gong)作(zuo)點下(xia)的(de)靜態電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)，伏安特(te)性(xing)曲線(xian)上的(de)斜率(lv)為(wei)(wei)動態電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。表達(da)非(fei)線(xian)性(xing)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)特(te)性(xing)的(de)方式比(bi)較復(fu)雜(za)，但這些非(fei)線(xian)性(xing)關系在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)(dian)(dian)路中得(de)到了廣泛的(de)應用。

2、按材料分類

a.線繞(rao)電(dian)(dian)阻(zu)器由電(dian)(dian)阻(zu)線繞(rao)成電(dian)(dian)阻(zu)器，用高(gao)阻(zu)合金(jin)線繞(rao)在絕緣骨(gu)架上制成，外面涂有耐(nai)熱(re)的釉絕緣層(ceng)或絕緣漆。繞(rao)線電(dian)(dian)阻(zu)具有較低的溫度系數(shu)，阻(zu)值精(jing)度高(gao)，穩定(ding)性(xing)好，耐(nai)熱(re)耐(nai)腐蝕(shi)，主要做精(jing)密大功率(lv)電(dian)(dian)阻(zu)使用，缺點是高(gao)頻性(xing)能差，時間常數(shu)大。

b.碳合成電阻器(qi)由碳及合成塑膠壓制成而(er)成。

c.碳膜電(dian)(dian)阻(zu)器(qi)(qi)在(zai)瓷管上鍍上一層碳而成，將結晶碳沉(chen)積在(zai)陶(tao)瓷棒骨架上制(zhi)成。碳膜電(dian)(dian)阻(zu)器(qi)(qi)成本低(di)、性能(neng)穩(wen)定(ding)、阻(zu)值范圍寬、溫度系數(shu)和電(dian)(dian)壓系數(shu)低(di)，是目前(qian)應(ying)用最廣泛的電(dian)(dian)阻(zu)器(qi)(qi)。

d.金(jin)(jin)屬(shu)膜(mo)電阻器(qi)在瓷(ci)管上(shang)鍍(du)上(shang)一層金(jin)(jin)屬(shu)而成，用真空蒸發(fa)的(de)方法將合金(jin)(jin)材料(liao)蒸鍍(du)于陶瓷(ci)棒(bang)骨架表面(mian)。金(jin)(jin)屬(shu)膜(mo)電阻比碳膜(mo)電阻的(de)精度高，穩定性好，噪聲，溫度系數小。在儀器(qi)儀表及通(tong)訊設備中(zhong)大量采用。

e.金屬氧(yang)化(hua)膜電阻(zu)器在瓷管上(shang)鍍上(shang)一(yi)層(ceng)氧(yang)化(hua)錫而成(cheng)，在絕緣(yuan)棒(bang)上(shang)沉積一(yi)層(ceng)金屬氧(yang)化(hua)物。由于(yu)其本(ben)身即是氧(yang)化(hua)物，所以高(gao)(gao)溫(wen)下穩定(ding)，耐熱沖擊，負載能力強。按用(yong)途分，有通用(yong)、精密、高(gao)(gao)頻、高(gao)(gao)壓(ya)、高(gao)(gao)阻(zu)、大(da)功率和電阻(zu)網絡等。

3、特殊電阻器

a.保(bao)(bao)險(xian)電阻(zu)(zu)：又叫熔斷(duan)電阻(zu)(zu)器(qi)，在正常情況下(xia)起著電阻(zu)(zu)和保(bao)(bao)險(xian)絲(si)的雙重作用(yong)，當電路(lu)出(chu)現故障而使(shi)其功率(lv)超過(guo)額(e)定功率(lv)時，它會像保(bao)(bao)險(xian)絲(si)一樣熔斷(duan)使(shi)連接電路(lu)斷(duan)開。保(bao)(bao)險(xian)絲(si)電阻(zu)(zu)一般電阻(zu)(zu)值(zhi)都小（0.33Ω～10KΩ），功率(lv)也較小。保(bao)(bao)險(xian)絲(si)電阻(zu)(zu)器(qi)常用(yong)型(xing)號有：RF10型(xing)、RF111-5保(bao)(bao)險(xian)絲(si)電阻(zu)(zu)器(qi)的符(fu)號型(xing)、RRD0910型(xing)、RRD0911型(xing)等。

b.敏(min)(min)(min)(min)感(gan)電(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)：是(shi)指(zhi)其(qi)電(dian)阻(zu)(zu)(zu)(zu)(zu)值(zhi)對于某種物(wu)理量（如溫度、濕度、光(guang)照、電(dian)壓、機械(xie)力、以及氣(qi)體(ti)濃度等）具有(you)敏(min)(min)(min)(min)感(gan)特性，當這些物(wu)理量發生變化時，敏(min)(min)(min)(min)感(gan)電(dian)阻(zu)(zu)(zu)(zu)(zu)的阻(zu)(zu)(zu)(zu)(zu)值(zhi)就會(hui)隨物(wu)理量變化而發生改變，呈現(xian)不同的電(dian)阻(zu)(zu)(zu)(zu)(zu)值(zhi)。根(gen)據對不同物(wu)理量敏(min)(min)(min)(min)感(gan)，敏(min)(min)(min)(min)感(gan)電(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)可分為熱敏(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)和氣(qi)敏(min)(min)(min)(min)等類型敏(min)(min)(min)(min)感(gan)電(dian)阻(zu)(zu)(zu)(zu)(zu)。敏(min)(min)(min)(min)感(gan)電(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)所用的材(cai)(cai)料幾乎(hu)都是(shi)半(ban)導體(ti)材(cai)(cai)料，這類電(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)也稱為半(ban)導體(ti)電(dian)阻(zu)(zu)(zu)(zu)(zu)器(qi)。

c.熱(re)敏電阻(zu)(zu)(zu)(zu)的阻(zu)(zu)(zu)(zu)值隨(sui)溫(wen)(wen)度(du)(du)(du)變化(hua)而變化(hua)，溫(wen)(wen)度(du)(du)(du)升高阻(zu)(zu)(zu)(zu)為負(fu)(fu)溫(wen)(wen)度(du)(du)(du)系(xi)數(shu)(shu)（NTC）熱(re)敏電阻(zu)(zu)(zu)(zu)。應用較多的是負(fu)(fu)溫(wen)(wen)度(du)(du)(du)系(xi)數(shu)(shu)熱(re)敏電阻(zu)(zu)(zu)(zu)，又可分為普通型(xing)(xing)負(fu)(fu)溫(wen)(wen)度(du)(du)(du)系(xi)數(shu)(shu)熱(re)敏電阻(zu)(zu)(zu)(zu)；穩壓(ya)型(xing)(xing)負(fu)(fu)溫(wen)(wen)度(du)(du)(du)系(xi)數(shu)(shu)熱(re)敏電阻(zu)(zu)(zu)(zu)；測(ce)溫(wen)(wen)型(xing)(xing)負(fu)(fu)溫(wen)(wen)度(du)(du)(du)系(xi)數(shu)(shu)熱(re)敏電阻(zu)(zu)(zu)(zu)等。光(guang)敏電阻(zu)(zu)(zu)(zu)是電阻(zu)(zu)(zu)(zu)的阻(zu)(zu)(zu)(zu)值隨(sui)入(ru)射光(guang)的強(qiang)弱變化(hua)而改變，當入(ru)射光(guang)增(zeng)強(qiang)時，光(guang)敏電阻(zu)(zu)(zu)(zu)的減(jian)小，入(ru)射光(guang)減(jian)弱時電阻(zu)(zu)(zu)(zu)值增(zeng)大。

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二、電阻器選用的方法

1、固定電阻器的選用

固定電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器有(you)多種(zhong)(zhong)類型(xing)，選擇哪一種(zhong)(zhong)材料和結構(gou)的電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，應(ying)根據應(ying)用(yong)電(dian)(dian)(dian)(dian)路(lu)的具體要求而(er)定。高頻電(dian)(dian)(dian)(dian)路(lu)應(ying)選用(yong)分布電(dian)(dian)(dian)(dian)感和分布電(dian)(dian)(dian)(dian)容小(xiao)的非線(xian)繞電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，例(li)如碳膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器、金(jin)(jin)屬電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器和金(jin)(jin)屬氧化膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，薄膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，厚(hou)膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，合(he)金(jin)(jin)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，防腐(fu)蝕鍍(du)膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器等(deng)。高增益(yi)小(xiao)信號放大(da)電(dian)(dian)(dian)(dian)路(lu)應(ying)選用(yong)低噪(zao)聲(sheng)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，例(li)如金(jin)(jin)屬膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器、碳膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器和線(xian)繞電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器，而(er)不能使(shi)用(yong)噪(zao)聲(sheng)較(jiao)大(da)的合(he)成碳膜(mo)(mo)(mo)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器和有(you)機實心電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)器。

所(suo)選(xuan)電(dian)(dian)(dian)(dian)阻(zu)器的(de)電(dian)(dian)(dian)(dian)阻(zu)值應(ying)接(jie)近應(ying)用(yong)電(dian)(dian)(dian)(dian)路中(zhong)計算值的(de)一個標稱(cheng)值，應(ying)優先選(xuan)用(yong)標準系列(lie)的(de)電(dian)(dian)(dian)(dian)阻(zu)器。一般(ban)電(dian)(dian)(dian)(dian)路使(shi)用(yong)的(de)電(dian)(dian)(dian)(dian)阻(zu)器允許誤差為(wei)±5%~±10%。精密(mi)儀器及(ji)特殊電(dian)(dian)(dian)(dian)路中(zhong)使(shi)用(yong)的(de)電(dian)(dian)(dian)(dian)阻(zu)器，應(ying)選(xuan)用(yong)精密(mi)電(dian)(dian)(dian)(dian)阻(zu)器，對(dui)精密(mi)度為(wei)1%以(yi)內的(de)電(dian)(dian)(dian)(dian)阻(zu)，如0.01%，0.1%，0.5%這些量級的(de)電(dian)(dian)(dian)(dian)阻(zu)應(ying)采用(yong)捷比信電(dian)(dian)(dian)(dian)阻(zu)。所(suo)選(xuan)電(dian)(dian)(dian)(dian)阻(zu)器的(de)額定功(gong)率，要符(fu)合應(ying)用(yong)電(dian)(dian)(dian)(dian)路中(zhong)對(dui)電(dian)(dian)(dian)(dian)阻(zu)器功(gong)率容量的(de)要求，一般(ban)不應(ying)隨意(yi)加大或減小電(dian)(dian)(dian)(dian)阻(zu)器的(de)功(gong)率。

若(ruo)電(dian)(dian)路(lu)(lu)要(yao)(yao)求是功(gong)率型(xing)電(dian)(dian)阻器，則其(qi)額定(ding)功(gong)率可(ke)高于實際應用(yong)電(dian)(dian)路(lu)(lu)要(yao)(yao)求功(gong)率的1~2倍。

2、熔斷電阻器的選用

熔斷電阻(zu)器具有(you)保(bao)護功能(neng)(neng)的電阻(zu)器。選用時應考慮其(qi)雙重性(xing)能(neng)(neng)，根據電路的具體要(yao)求選擇其(qi)阻(zu)值(zhi)和(he)功率(lv)等參數(shu)。既要(yao)保(bao)證它(ta)在(zai)過負荷時能(neng)(neng)快速熔斷，又要(yao)保(bao)證它(ta)在(zai)正常條件(jian)下能(neng)(neng)長期穩定的工作(zuo)。電阻(zu)值(zhi)過大(da)或功率(lv)過大(da)，均不能(neng)(neng)起到保(bao)護作(zuo)用。

三、電阻器選用的基本原則

1、選擇通過認(ren)(ren)證(zheng)(zheng)機構(gou)認(ren)(ren)證(zheng)(zheng)的(de)生產線(xian)制造出的(de)執行高水平標準的(de)電阻器(qi)。

2、選(xuan)擇(ze)具備功能(neng)優(you)(you)(you)勢(shi)、質量(liang)優(you)(you)(you)勢(shi)、效率(lv)優(you)(you)(you)勢(shi)、功能(neng)價(jia)格比(bi)優(you)(you)(you)勢(shi)、服務優(you)(you)(you)勢(shi)的制造商生產的電阻器(qi)。

3、選擇能滿足上述要求的上型號目錄的制造商，并向其直接訂購電阻器。