選擇電阻至少要從以下五個因素考慮：電阻類型、額定功率、額定電壓、溫度系數、精度。下面深圳旺詮合金電阻代理商和你簡單說下這(zhe)5個因素。

一、電阻(zu)類型(xing)。電阻(zu)有很(hen)多(duo)類型(xing)，這(zhe)里就不一一講解了。一般買電阻(zu)的(de)都知(zhi)道自己要啥類型(xing)的(de)。

二、電阻額定(ding)(ding)功(gong)率。電阻的(de)(de)(de)額定(ding)(ding)功(gong)率是由電阻所承受的(de)(de)(de)熱點溫(wen)度(du)確定(ding)(ding)的(de)(de)(de)，由于電阻受環境溫(wen)度(du)的(de)(de)(de)影響很大。這個(ge)要根據應用的(de)(de)(de)電路結合來(lai)選，一般(ban)工程師都(dou)知道(dao)(dao)的(de)(de)(de)，不知道(dao)(dao)采購可以問自家(jia)工程師。

三、電(dian)(dian)(dian)阻(zu)(zu)額定(ding)電(dian)(dian)(dian)壓。當電(dian)(dian)(dian)阻(zu)(zu)額定(ding)功率(lv)一定(ding)時，額定(ding)工(gong)作電(dian)(dian)(dian)壓隨(sui)電(dian)(dian)(dian)阻(zu)(zu)R的增(zeng)大(da)而(er)增(zeng)高但隨(sui)著電(dian)(dian)(dian)壓的增(zeng)高，流(liu)過電(dian)(dian)(dian)阻(zu)(zu)的電(dian)(dian)(dian)流(liu)密度也(ye)會變大(da)，從而(er)導致電(dian)(dian)(dian)阻(zu)(zu)局部發(fa)熱嚴重(zhong)，久而(er)久之電(dian)(dian)(dian)阻(zu)(zu)容易老化并(bing)失效。

四、電(dian)(dian)阻(zu)溫度系數(shu)在環境溫度以及電(dian)(dian)阻(zu)自身發熱(re)影響下，電(dian)(dian)阻(zu)的(de)阻(zu)值將產生(sheng)漂移，也就是(shi)我們說的(de)溫漂，電(dian)(dian)阻(zu)溫度系數(shu)主要取決于電(dian)(dian)阻(zu)材料的(de)電(dian)(dian)阻(zu)率與(yu)環境溫度。

五(wu)、電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)精(jing)度(du)。電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)精(jing)度(du)是選擇(ze)硬件電(dian)(dian)(dian)(dian)路(lu)(lu)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)的(de)一個重要(yao)考(kao)慮(lv)因素，一般(ban)對阻(zu)(zu)(zu)值(zhi)不嚴格的(de)電(dian)(dian)(dian)(dian)路(lu)(lu)沒(mei)必要(yao)用精(jing)度(du)很高的(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)，但是對于儀器儀表、電(dian)(dian)(dian)(dian)流電(dian)(dian)(dian)(dian)測(ce)電(dian)(dian)(dian)(dian)路(lu)(lu)、電(dian)(dian)(dian)(dian)壓檢測(ce)電(dian)(dian)(dian)(dian)路(lu)(lu)等，對電(dian)(dian)(dian)(dian)流或(huo)者其(qi)他對阻(zu)(zu)(zu)值(zhi)波動影響很大(da)的(de)電(dian)(dian)(dian)(dian)路(lu)(lu)需要(yao)用精(jing)度(du)電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)，有些(xie)電(dian)(dian)(dian)(dian)路(lu)(lu)甚至用到0.01%高的(de)精(jing)密電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)。