一、電阻的種類有哪些

1、按伏安特性分類

可分為(wei)線性(xing)電(dian)阻和非(fei)線性(xing)電(dian)阻。對大多(duo)數導體來說，在一(yi)定(ding)的(de)溫度下，其電(dian)阻幾(ji)乎維持不變而為(wei)一(yi)定(ding)值(zhi)，這類電(dian)阻稱為(wei)線性(xing)電(dian)阻。

有些材料的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)明顯地隨著電(dian)(dian)(dian)(dian)流（或(huo)電(dian)(dian)(dian)(dian)壓(ya)）而(er)變化(hua)，其伏安特(te)性(xing)(xing)是一條曲(qu)線(xian)(xian)，這(zhe)類電(dian)(dian)(dian)(dian)阻(zu)(zu)稱為(wei)非線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)。非線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)在某一給定的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)（或(huo)電(dian)(dian)(dian)(dian)流）作用(yong)下，電(dian)(dian)(dian)(dian)壓(ya)與電(dian)(dian)(dian)(dian)流的(de)(de)比(bi)值為(wei)在該工作點(dian)下的(de)(de)靜態(tai)電(dian)(dian)(dian)(dian)阻(zu)(zu)，伏安特(te)性(xing)(xing)曲(qu)線(xian)(xian)上的(de)(de)斜率為(wei)動態(tai)電(dian)(dian)(dian)(dian)阻(zu)(zu)。表達非線(xian)(xian)性(xing)(xing)電(dian)(dian)(dian)(dian)阻(zu)(zu)特(te)性(xing)(xing)的(de)(de)方(fang)式比(bi)較復雜(za)，但這(zhe)些非線(xian)(xian)性(xing)(xing)關系在電(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)路中得到(dao)了廣(guang)泛的(de)(de)應用(yong)。

2、按材料分類

a.線(xian)繞(rao)電阻(zu)(zu)(zu)器由電阻(zu)(zu)(zu)線(xian)繞(rao)成電阻(zu)(zu)(zu)器，用高阻(zu)(zu)(zu)合金線(xian)繞(rao)在絕緣骨(gu)架上制(zhi)成，外面涂有耐熱(re)的(de)釉絕緣層(ceng)或絕緣漆(qi)。繞(rao)線(xian)電阻(zu)(zu)(zu)具有較低的(de)溫度系數，阻(zu)(zu)(zu)值精度高，穩定性好，耐熱(re)耐腐蝕，主要做精密大功率電阻(zu)(zu)(zu)使(shi)用，缺點是高頻性能差，時間常數大。

b.碳合(he)成(cheng)電阻器由碳及合(he)成(cheng)塑(su)膠壓制(zhi)成(cheng)而成(cheng)。

c.碳(tan)(tan)膜(mo)電阻器(qi)在(zai)瓷(ci)管上鍍上一層碳(tan)(tan)而成，將結晶碳(tan)(tan)沉積在(zai)陶(tao)瓷(ci)棒骨架上制成。碳(tan)(tan)膜(mo)電阻器(qi)成本低、性能穩(wen)定(ding)、阻值范(fan)圍寬、溫(wen)度系數和電壓系數低，是目前應用(yong)最廣泛的電阻器(qi)。

d.金(jin)(jin)屬(shu)膜(mo)(mo)電(dian)阻器在瓷管上鍍上一(yi)層金(jin)(jin)屬(shu)而成，用真(zhen)空(kong)蒸(zheng)發的方法將(jiang)合金(jin)(jin)材料蒸(zheng)鍍于(yu)陶瓷棒骨架表面(mian)。金(jin)(jin)屬(shu)膜(mo)(mo)電(dian)阻比碳膜(mo)(mo)電(dian)阻的精度(du)高，穩定性好，噪聲，溫度(du)系數(shu)小(xiao)。在儀(yi)(yi)器儀(yi)(yi)表及通訊設備中(zhong)大量采用。

e.金(jin)屬氧化(hua)膜電(dian)阻器(qi)在瓷管上(shang)(shang)鍍上(shang)(shang)一(yi)層(ceng)氧化(hua)錫而成，在絕緣棒(bang)上(shang)(shang)沉積(ji)一(yi)層(ceng)金(jin)屬氧化(hua)物(wu)(wu)。由(you)于其本身(shen)即是(shi)氧化(hua)物(wu)(wu)，所以高(gao)溫下穩定，耐熱沖擊，負載能力強。按用途分，有通用、精密、高(gao)頻(pin)、高(gao)壓、高(gao)阻、大功率和電(dian)阻網絡(luo)等(deng)。

3、特殊電阻器

a.保險(xian)電(dian)阻(zu)：又叫熔斷電(dian)阻(zu)器(qi)，在正常(chang)情況下(xia)起著電(dian)阻(zu)和(he)保險(xian)絲的雙重(zhong)作用，當(dang)電(dian)路出現故(gu)障而使其(qi)功率(lv)超過額定功率(lv)時，它會(hui)像保險(xian)絲一樣熔斷使連接電(dian)路斷開。保險(xian)絲電(dian)阻(zu)一般(ban)電(dian)阻(zu)值都(dou)小（0.33Ω～10KΩ），功率(lv)也(ye)較小。保險(xian)絲電(dian)阻(zu)器(qi)常(chang)用型號有：RF10型、RF111-5保險(xian)絲電(dian)阻(zu)器(qi)的符號型、RRD0910型、RRD0911型等。

b.敏(min)(min)(min)感(gan)(gan)電(dian)阻(zu)(zu)器：是指其電(dian)阻(zu)(zu)值對于某種物理(li)量(liang)（如溫(wen)度、濕(shi)度、光照、電(dian)壓、機械力、以及氣(qi)體(ti)濃(nong)度等）具(ju)有敏(min)(min)(min)感(gan)(gan)特性(xing)，當(dang)這(zhe)些物理(li)量(liang)發生變化時，敏(min)(min)(min)感(gan)(gan)電(dian)阻(zu)(zu)的阻(zu)(zu)值就(jiu)會隨物理(li)量(liang)變化而發生改變，呈現不同的電(dian)阻(zu)(zu)值。根據對不同物理(li)量(liang)敏(min)(min)(min)感(gan)(gan)，敏(min)(min)(min)感(gan)(gan)電(dian)阻(zu)(zu)器可分為(wei)熱(re)敏(min)(min)(min)、濕(shi)敏(min)(min)(min)、光敏(min)(min)(min)、壓敏(min)(min)(min)、力敏(min)(min)(min)、磁敏(min)(min)(min)和(he)氣(qi)敏(min)(min)(min)等類型敏(min)(min)(min)感(gan)(gan)電(dian)阻(zu)(zu)。敏(min)(min)(min)感(gan)(gan)電(dian)阻(zu)(zu)器所用(yong)的材料幾(ji)乎都是半導(dao)體(ti)材料，這(zhe)類電(dian)阻(zu)(zu)器也稱為(wei)半導(dao)體(ti)電(dian)阻(zu)(zu)器。

c.熱敏(min)電(dian)(dian)阻的(de)(de)阻值(zhi)隨溫度(du)(du)變化而變化，溫度(du)(du)升高阻為負溫度(du)(du)系數（NTC）熱敏(min)電(dian)(dian)阻。應用(yong)較多的(de)(de)是負溫度(du)(du)系數熱敏(min)電(dian)(dian)阻，又可分(fen)為普通型(xing)負溫度(du)(du)系數熱敏(min)電(dian)(dian)阻；穩壓型(xing)負溫度(du)(du)系數熱敏(min)電(dian)(dian)阻；測溫型(xing)負溫度(du)(du)系數熱敏(min)電(dian)(dian)阻等。光(guang)(guang)敏(min)電(dian)(dian)阻是電(dian)(dian)阻的(de)(de)阻值(zhi)隨入(ru)射(she)光(guang)(guang)的(de)(de)強(qiang)(qiang)弱變化而改變，當入(ru)射(she)光(guang)(guang)增(zeng)強(qiang)(qiang)時(shi)，光(guang)(guang)敏(min)電(dian)(dian)阻的(de)(de)減小，入(ru)射(she)光(guang)(guang)減弱時(shi)電(dian)(dian)阻值(zhi)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(ding)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)有多(duo)種類型(xing)，選(xuan)擇哪一種材料和(he)結構的(de)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，應根據(ju)應用電(dian)(dian)路(lu)(lu)的(de)具體要求而(er)定(ding)。高頻電(dian)(dian)路(lu)(lu)應選(xuan)用分布電(dian)(dian)感和(he)分布電(dian)(dian)容小的(de)非(fei)線繞電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，例(li)如碳(tan)(tan)膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)、金屬電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)和(he)金屬氧化膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，薄膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，厚(hou)膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，合(he)金電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，防腐蝕鍍膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)等。高增益小信號(hao)放大電(dian)(dian)路(lu)(lu)應選(xuan)用低噪聲電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，例(li)如金屬膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)、碳(tan)(tan)膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)和(he)線繞電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)，而(er)不能使用噪聲較(jiao)大的(de)合(he)成碳(tan)(tan)膜(mo)電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)和(he)有機實心電(dian)(dian)阻(zu)(zu)(zu)(zu)器(qi)(qi)(qi)。

所(suo)選電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)值應(ying)(ying)(ying)(ying)接近應(ying)(ying)(ying)(ying)用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中計算值的一(yi)個標稱(cheng)值，應(ying)(ying)(ying)(ying)優先選用(yong)(yong)標準系列的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)。一(yi)般電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)使用(yong)(yong)的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)允許誤差為±5%~±10%。精(jing)密(mi)儀器(qi)(qi)及特殊電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中使用(yong)(yong)的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)，應(ying)(ying)(ying)(ying)選用(yong)(yong)精(jing)密(mi)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)，對精(jing)密(mi)度為1%以內(nei)的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)，如0.01%，0.1%，0.5%這些(xie)量級(ji)的電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)應(ying)(ying)(ying)(ying)采用(yong)(yong)捷比信電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)。所(suo)選電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)的額(e)定功(gong)(gong)率，要符(fu)合應(ying)(ying)(ying)(ying)用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中對電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)功(gong)(gong)率容量的要求，一(yi)般不應(ying)(ying)(ying)(ying)隨意加大或減小(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)的功(gong)(gong)率。

若電(dian)路(lu)要求(qiu)是功(gong)率(lv)型電(dian)阻器，則其額定功(gong)率(lv)可高于實際應用電(dian)路(lu)要求(qiu)功(gong)率(lv)的1~2倍。

2、熔斷電阻器的選用

熔斷電(dian)阻(zu)器(qi)(qi)具(ju)有保(bao)護(hu)功能的(de)電(dian)阻(zu)器(qi)(qi)。選用時應考(kao)慮其雙重性能，根據電(dian)路的(de)具(ju)體要求(qiu)選擇其阻(zu)值和功率等參(can)數。既(ji)要保(bao)證(zheng)它在過負(fu)荷時能快速熔斷，又要保(bao)證(zheng)它在正(zheng)常條(tiao)件下能長期(qi)穩(wen)定的(de)工作。電(dian)阻(zu)值過大或功率過大，均不(bu)能起(qi)到保(bao)護(hu)作用。

三、電阻器選用的基本原則

1、選擇通(tong)過認(ren)證(zheng)機構(gou)認(ren)證(zheng)的生產線制造出的執行高(gao)水(shui)平標準的電阻器。

2、選擇具備(bei)功(gong)能(neng)優勢(shi)(shi)(shi)、質(zhi)量優勢(shi)(shi)(shi)、效率(lv)優勢(shi)(shi)(shi)、功(gong)能(neng)價格比優勢(shi)(shi)(shi)、服務優勢(shi)(shi)(shi)的制造(zao)商生(sheng)產的電阻器。

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。