一、電壓表可以用來干嘛

電(dian)(dian)壓(ya)(ya)表是(shi)用來測(ce)電(dian)(dian)壓(ya)(ya)的大小的儀器，在電(dian)(dian)路(lu)中(zhong)的符(fu)號為?。電(dian)(dian)壓(ya)(ya)表的電(dian)(dian)阻(zu)非常大，可以當(dang)成開路(lu)。

使用電壓表時應注意以下幾點：

1、測電(dian)壓(ya)時(shi)，必(bi)須(xu)把電(dian)壓(ya)表并聯在被測電(dian)路的(de)兩(liang)端。如(ru)果電(dian)壓(ya)表與被測用(yong)電(dian)器(qi)串聯，則(ze)不能測出(chu)用(yong)電(dian)器(qi)兩(liang)端的(de)電(dian)壓(ya)。

2、“+”“-”接線柱不(bu)能(neng)接反。如(ru)果電(dian)(dian)流(liu)從(cong)電(dian)(dian)壓表的“-”接線柱流(liu)進，從(cong)“＋”接線柱流(liu)出，則指針反轉，不(bu)能(neng)測出電(dian)(dian)壓，且容(rong)易損壞電(dian)(dian)壓表。

3、正確選(xuan)擇量(liang)(liang)(liang)(liang)程，被測(ce)電(dian)壓(ya)(ya)不(bu)要超(chao)過電(dian)壓(ya)(ya)表(biao)(biao)(biao)的(de)量(liang)(liang)(liang)(liang)程，測(ce)量(liang)(liang)(liang)(liang)前(qian)先用(yong)電(dian)壓(ya)(ya)表(biao)(biao)(biao)的(de)大(da)量(liang)(liang)(liang)(liang)程，采(cai)用(yong)“試觸法(fa)”估(gu)計被測(ce)電(dian)壓(ya)(ya)的(de)大(da)小(xiao)。試觸時，如果指針(zhen)偏轉(zhuan)角度(du)超(chao)過滿(man)偏角度(du)，則(ze)被測(ce)電(dian)壓(ya)(ya)過大(da)，無法(fa)測(ce)量(liang)(liang)(liang)(liang)且(qie)容(rong)易損壞電(dian)壓(ya)(ya)表(biao)(biao)(biao)。必須換用(yong)更(geng)大(da)量(liang)(liang)(liang)(liang)程的(de)電(dian)壓(ya)(ya)表(biao)(biao)(biao)進(jin)(jin)行(xing)測(ce)量(liang)(liang)(liang)(liang)。如果指針(zhen)正常偏轉(zhuan)，則(ze)用(yong)該(gai)量(liang)(liang)(liang)(liang)程進(jin)(jin)行(xing)測(ce)量(liang)(liang)(liang)(liang)。如果指針(zhen)的(de)偏轉(zhuan)角度(du)非常小(xiao)，則(ze)應該(gai)換用(yong)較小(xiao)量(liang)(liang)(liang)(liang)程進(jin)(jin)行(xing)測(ce)量(liang)(liang)(liang)(liang)。

二、電壓表可以直接接在電源兩極上嗎

前文已經簡單了解了電壓表是用來干嘛的，那么在使用電壓表測量電壓的時候，電壓表可以直接接在電源兩極上嗎？

電(dian)(dian)(dian)壓(ya)(ya)表可(ke)直接接在(zai)電(dian)(dian)(dian)源兩極上，此(ci)時測出(chu)的電(dian)(dian)(dian)壓(ya)(ya)為電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)(ya)。當(dang)然，量程(cheng)必須合適，如果電(dian)(dian)(dian)壓(ya)(ya)表量程(cheng)小于(yu)電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)(ya)，則可(ke)能(neng)會燒壞電(dian)(dian)(dian)壓(ya)(ya)表。