一、電壓表怎么看測量對象

判斷電(dian)壓(ya)表測量的是電(dian)路中(zhong)(zhong)哪(na)一部分的電(dian)壓(ya)，這類題目在(zai)(zai)練習和試題中(zhong)(zhong)頻(pin)頻(pin)出現(xian)，由于電(dian)壓(ya)表與用電(dian)器并聯(lian)，在(zai)(zai)串聯(lian)電(dian)路中(zhong)(zhong)，不論(lun)是實物(wu)電(dian)路還是形式有變化的電(dian)路圖中(zhong)(zhong)，學生往往不能快速準確地判斷電(dian)壓(ya)表究竟(jing)測量的是哪(na)一部分的電(dian)壓(ya)，基于上述原(yuan)因，給出以下方法：

1、短路法

電壓表去掉，假設用導線接該(gai)位置，若此(ci)時某些(xie)用電(dian)器或(huo)電(dian)源被(bei)短路(lu)，則這些(xie)用電(dian)器或(huo)電(dian)源即為該(gai)電(dian)壓表(biao)測量的對象(xiang)。

2、去源法

“去掉”電(dian)(dian)源(yuan)（用手捂住(zhu)電(dian)(dian)源(yuan)），再看電(dian)(dian)壓表與哪(na)部分構成閉(bi)合回(hui)路(lu)，那么電(dian)(dian)壓表測(ce)的(de)就是那部分電(dian)(dian)路(lu)的(de)電(dian)(dian)壓。

3、滑線法

電(dian)(dian)壓表(biao)兩(liang)端沿著連接的導線滑動(dong)到(dao)用電(dian)(dian)器(qi)(qi)或電(dian)(dian)源(yuan)兩(liang)端。（能跨過元件：開關(guan)、電(dian)(dian)流表(biao)。不(bu)能跨過元件：電(dian)(dian)源(yuan)、用電(dian)(dian)器(qi)(qi)、電(dian)(dian)壓表(biao)）。

4、特殊說明

（1）電壓表(biao)接在電路中相當于該處開路。

（2）電(dian)流表接在(zai)電(dian)路中相(xiang)當于一根導線。

（3）電壓表與用電器串聯拖后接在電源(yuan)兩(liang)端(duan)，電壓表測量的是電源(yuan)電壓。

二、電壓表測量對象短路會怎么樣

被測(ce)試(shi)(shi)的(de)(de)用(yong)電(dian)(dian)(dian)(dian)器(qi)短(duan)路的(de)(de)時(shi)(shi)候，電(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)顯(xian)示為(wei)(wei)零，被測(ce)試(shi)(shi)的(de)(de)用(yong)電(dian)(dian)(dian)(dian)器(qi)斷路的(de)(de)時(shi)(shi)候，通常很多人會認為(wei)(wei)被測(ce)試(shi)(shi)是(shi)開(kai)路電(dian)(dian)(dian)(dian)壓(ya)(ya)。實際(ji)并不(bu)準確(que)，只(zhi)有輸(shu)入電(dian)(dian)(dian)(dian)壓(ya)(ya)與(yu)被測(ce)試(shi)(shi)的(de)(de)用(yong)電(dian)(dian)(dian)(dian)器(qi)直接相連的(de)(de)情況下，斷路之后，電(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)測(ce)試(shi)(shi)出來(lai)才是(shi)開(kai)路電(dian)(dian)(dian)(dian)壓(ya)(ya)。但是(shi)如果輸(shu)入電(dian)(dian)(dian)(dian)壓(ya)(ya)與(yu)被測(ce)試(shi)(shi)的(de)(de)用(yong)電(dian)(dian)(dian)(dian)器(qi)之間有其(qi)他(ta)感(gan)(gan)容電(dian)(dian)(dian)(dian)子元件的(de)(de)話，受到感(gan)(gan)容電(dian)(dian)(dian)(dian)子元件的(de)(de)影響，測(ce)試(shi)(shi)出來(lai)的(de)(de)實際(ji)是(shi)頻率(lv)電(dian)(dian)(dian)(dian)壓(ya)(ya)。