一、電阻的種類有哪些

1、按伏安特性分類

可分為線性電(dian)(dian)阻和非線性電(dian)(dian)阻。對(dui)大(da)多(duo)數導體(ti)來說，在一(yi)定的溫(wen)度下，其電(dian)(dian)阻幾乎(hu)維(wei)持不(bu)變(bian)而(er)為一(yi)定值，這類電(dian)(dian)阻稱為線性電(dian)(dian)阻。

有些材料的(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)明(ming)顯地隨著電(dian)(dian)(dian)(dian)流(liu)（或電(dian)(dian)(dian)(dian)壓）而(er)變(bian)化，其伏安(an)特性(xing)(xing)(xing)是一條曲線，這(zhe)類電(dian)(dian)(dian)(dian)阻(zu)(zu)稱為(wei)(wei)非(fei)線性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)。非(fei)線性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)在(zai)(zai)某一給定的(de)電(dian)(dian)(dian)(dian)壓（或電(dian)(dian)(dian)(dian)流(liu)）作用(yong)下，電(dian)(dian)(dian)(dian)壓與電(dian)(dian)(dian)(dian)流(liu)的(de)比值為(wei)(wei)在(zai)(zai)該工(gong)作點下的(de)靜(jing)態(tai)電(dian)(dian)(dian)(dian)阻(zu)(zu)，伏安(an)特性(xing)(xing)(xing)曲線上的(de)斜率為(wei)(wei)動態(tai)電(dian)(dian)(dian)(dian)阻(zu)(zu)。表達(da)非(fei)線性(xing)(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)特性(xing)(xing)(xing)的(de)方式比較復(fu)雜(za)，但這(zhe)些非(fei)線性(xing)(xing)(xing)關系在(zai)(zai)電(dian)(dian)(dian)(dian)子(zi)電(dian)(dian)(dian)(dian)路中(zhong)得到(dao)了廣泛的(de)應(ying)用(yong)。

2、按材料分類

a.線繞(rao)電阻(zu)器(qi)由電阻(zu)線繞(rao)成(cheng)電阻(zu)器(qi)，用(yong)高阻(zu)合金線繞(rao)在絕緣(yuan)骨架(jia)上制成(cheng)，外面涂有耐熱的釉絕緣(yuan)層或絕緣(yuan)漆。繞(rao)線電阻(zu)具(ju)有較低的溫度(du)系數(shu)，阻(zu)值精(jing)度(du)高，穩定性好，耐熱耐腐蝕，主(zhu)要做精(jing)密大(da)功率(lv)電阻(zu)使用(yong)，缺(que)點是高頻性能差(cha)，時間常(chang)數(shu)大(da)。

b.碳(tan)合成電阻器由碳(tan)及合成塑膠壓制成而(er)成。

c.碳膜(mo)電(dian)(dian)阻器在(zai)瓷管上鍍上一層碳而成，將結(jie)晶碳沉積在(zai)陶瓷棒骨(gu)架(jia)上制成。碳膜(mo)電(dian)(dian)阻器成本低、性能穩定、阻值范圍寬、溫度系(xi)數和(he)電(dian)(dian)壓(ya)系(xi)數低，是目前(qian)應(ying)用(yong)最廣泛的電(dian)(dian)阻器。

d.金屬(shu)膜(mo)電阻(zu)(zu)(zu)器(qi)在瓷(ci)管上(shang)鍍(du)上(shang)一層金屬(shu)而成，用真(zhen)空蒸發的方法將(jiang)合金材料(liao)蒸鍍(du)于(yu)陶瓷(ci)棒骨架表面。金屬(shu)膜(mo)電阻(zu)(zu)(zu)比碳(tan)膜(mo)電阻(zu)(zu)(zu)的精度高，穩定性(xing)好(hao)，噪聲，溫(wen)度系數小(xiao)。在儀器(qi)儀表及(ji)通訊設備中大量采用。

e.金(jin)屬氧化(hua)膜電阻(zu)器(qi)在瓷管上(shang)鍍上(shang)一(yi)層氧化(hua)錫而(er)成，在絕緣(yuan)棒上(shang)沉積(ji)一(yi)層金(jin)屬氧化(hua)物。由于其(qi)本身即是氧化(hua)物，所以高溫(wen)下(xia)穩定(ding)，耐熱沖擊(ji)，負載能力強。按(an)用(yong)途(tu)分，有(you)通用(yong)、精密、高頻、高壓(ya)、高阻(zu)、大功率和電阻(zu)網(wang)絡等。

3、特殊電阻器

a.保(bao)(bao)(bao)險電(dian)(dian)阻(zu)：又叫熔(rong)斷(duan)電(dian)(dian)阻(zu)器(qi)，在正常情況(kuang)下起(qi)著電(dian)(dian)阻(zu)和保(bao)(bao)(bao)險絲(si)的雙重作用(yong)，當電(dian)(dian)路出(chu)現(xian)故障而(er)使(shi)其(qi)功(gong)率(lv)超(chao)過額(e)定功(gong)率(lv)時，它(ta)會像(xiang)保(bao)(bao)(bao)險絲(si)一樣熔(rong)斷(duan)使(shi)連接電(dian)(dian)路斷(duan)開。保(bao)(bao)(bao)險絲(si)電(dian)(dian)阻(zu)一般電(dian)(dian)阻(zu)值都小（0.33Ω～10KΩ），功(gong)率(lv)也較小。保(bao)(bao)(bao)險絲(si)電(dian)(dian)阻(zu)器(qi)常用(yong)型(xing)號(hao)有(you)：RF10型(xing)、RF111-5保(bao)(bao)(bao)險絲(si)電(dian)(dian)阻(zu)器(qi)的符號(hao)型(xing)、RRD0910型(xing)、RRD0911型(xing)等。

b.敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)器(qi)：是指其電(dian)(dian)阻(zu)(zu)值(zhi)對于某種物(wu)理(li)量（如溫度(du)、濕(shi)度(du)、光(guang)(guang)照(zhao)、電(dian)(dian)壓、機(ji)械力、以(yi)及(ji)氣體濃度(du)等）具有敏(min)(min)感(gan)特性，當這些物(wu)理(li)量發生變化(hua)(hua)時(shi)，敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)的阻(zu)(zu)值(zhi)就會隨物(wu)理(li)量變化(hua)(hua)而發生改變，呈現不同的電(dian)(dian)阻(zu)(zu)值(zhi)。根據(ju)對不同物(wu)理(li)量敏(min)(min)感(gan)，敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)器(qi)可分(fen)為熱敏(min)(min)、濕(shi)敏(min)(min)、光(guang)(guang)敏(min)(min)、壓敏(min)(min)、力敏(min)(min)、磁敏(min)(min)和氣敏(min)(min)等類(lei)型敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)。敏(min)(min)感(gan)電(dian)(dian)阻(zu)(zu)器(qi)所(suo)用的材料幾乎都是半導體材料，這類(lei)電(dian)(dian)阻(zu)(zu)器(qi)也稱(cheng)為半導體電(dian)(dian)阻(zu)(zu)器(qi)。

c.熱敏(min)(min)電(dian)(dian)阻(zu)的(de)(de)阻(zu)值(zhi)隨(sui)溫(wen)(wen)(wen)度變(bian)(bian)化(hua)而變(bian)(bian)化(hua)，溫(wen)(wen)(wen)度升高阻(zu)為負(fu)溫(wen)(wen)(wen)度系(xi)數(shu)（NTC）熱敏(min)(min)電(dian)(dian)阻(zu)。應(ying)用較多的(de)(de)是負(fu)溫(wen)(wen)(wen)度系(xi)數(shu)熱敏(min)(min)電(dian)(dian)阻(zu)，又可分為普通型(xing)(xing)負(fu)溫(wen)(wen)(wen)度系(xi)數(shu)熱敏(min)(min)電(dian)(dian)阻(zu)；穩壓型(xing)(xing)負(fu)溫(wen)(wen)(wen)度系(xi)數(shu)熱敏(min)(min)電(dian)(dian)阻(zu)；測溫(wen)(wen)(wen)型(xing)(xing)負(fu)溫(wen)(wen)(wen)度系(xi)數(shu)熱敏(min)(min)電(dian)(dian)阻(zu)等。光(guang)(guang)(guang)敏(min)(min)電(dian)(dian)阻(zu)是電(dian)(dian)阻(zu)的(de)(de)阻(zu)值(zhi)隨(sui)入(ru)射光(guang)(guang)(guang)的(de)(de)強(qiang)弱變(bian)(bian)化(hua)而改變(bian)(bian)，當入(ru)射光(guang)(guang)(guang)增強(qiang)時(shi)，光(guang)(guang)(guang)敏(min)(min)電(dian)(dian)阻(zu)的(de)(de)減小，入(ru)射光(guang)(guang)(guang)減弱時(shi)電(dian)(dian)阻(zu)值(zhi)增大(da)。

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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)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)有多種(zhong)類型，選擇哪一種(zhong)材料和(he)結構的(de)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，應根據應用(yong)(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)路的(de)具(ju)體要求而定。高頻電(dian)(dian)(dian)(dian)(dian)(dian)路應選用(yong)(yong)(yong)(yong)分布電(dian)(dian)(dian)(dian)(dian)(dian)感和(he)分布電(dian)(dian)(dian)(dian)(dian)(dian)容小(xiao)的(de)非線繞電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，例如碳膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)、金(jin)屬(shu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)和(he)金(jin)屬(shu)氧化膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，薄(bo)膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，厚膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，合金(jin)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，防腐蝕鍍(du)膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)等。高增(zeng)益小(xiao)信(xin)號(hao)放大電(dian)(dian)(dian)(dian)(dian)(dian)路應選用(yong)(yong)(yong)(yong)低噪聲電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，例如金(jin)屬(shu)膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)、碳膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)和(he)線繞電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)，而不能(neng)使(shi)用(yong)(yong)(yong)(yong)噪聲較(jiao)大的(de)合成碳膜(mo)(mo)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)和(he)有機實心電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)(qi)(qi)。

所選電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)值(zhi)應(ying)接近應(ying)用(yong)電(dian)(dian)(dian)(dian)路(lu)中(zhong)(zhong)(zhong)計算(suan)值(zhi)的(de)(de)一個標(biao)稱值(zhi)，應(ying)優先選用(yong)標(biao)準系列的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)。一般電(dian)(dian)(dian)(dian)路(lu)使用(yong)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)允許誤差(cha)為±5%~±10%。精密儀器(qi)(qi)及特殊電(dian)(dian)(dian)(dian)路(lu)中(zhong)(zhong)(zhong)使用(yong)的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)，應(ying)選用(yong)精密電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)，對精密度為1%以內的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)，如0.01%，0.1%，0.5%這些量(liang)級的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)應(ying)采用(yong)捷比(bi)信電(dian)(dian)(dian)(dian)阻(zu)(zu)。所選電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)額定功(gong)率(lv)(lv)，要(yao)符合應(ying)用(yong)電(dian)(dian)(dian)(dian)路(lu)中(zhong)(zhong)(zhong)對電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)功(gong)率(lv)(lv)容量(liang)的(de)(de)要(yao)求(qiu)，一般不應(ying)隨意加大或減小電(dian)(dian)(dian)(dian)阻(zu)(zu)器(qi)(qi)的(de)(de)功(gong)率(lv)(lv)。

若電(dian)路(lu)要(yao)求是功(gong)(gong)率型電(dian)阻器(qi)，則(ze)其額(e)定功(gong)(gong)率可高于實(shi)際應(ying)用電(dian)路(lu)要(yao)求功(gong)(gong)率的1~2倍。

2、熔斷電阻器的選用

熔斷(duan)電(dian)(dian)(dian)阻(zu)器具(ju)有保(bao)護(hu)功(gong)能的(de)(de)電(dian)(dian)(dian)阻(zu)器。選用時應考慮其雙(shuang)重(zhong)性能，根據電(dian)(dian)(dian)路(lu)的(de)(de)具(ju)體(ti)要求選擇其阻(zu)值和功(gong)率等(deng)參(can)數。既要保(bao)證它(ta)在過負荷(he)時能快(kuai)速熔斷(duan)，又要保(bao)證它(ta)在正常條件下(xia)能長期穩定的(de)(de)工(gong)作(zuo)。電(dian)(dian)(dian)阻(zu)值過大(da)或(huo)功(gong)率過大(da)，均不能起到(dao)保(bao)護(hu)作(zuo)用。

三、電阻器選用的基本原則

1、選擇(ze)通過認(ren)證(zheng)機構(gou)認(ren)證(zheng)的生(sheng)產線制(zhi)造出(chu)的執行高水平標準的電阻(zu)器(qi)。

2、選擇具備功能(neng)優(you)(you)勢(shi)(shi)、質量(liang)優(you)(you)勢(shi)(shi)、效率(lv)優(you)(you)勢(shi)(shi)、功能(neng)價(jia)格比優(you)(you)勢(shi)(shi)、服務優(you)(you)勢(shi)(shi)的(de)制造(zao)商生產的(de)電阻器。

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。