一、電流表和電壓表有什么區別

電流表(biao)和電壓表(biao)都是電力領(ling)域應用(yong)的(de)測(ce)量(liang)儀表(biao)，一(yi)個(ge)用(yong)來測(ce)電流，一(yi)個(ge)用(yong)來測(ce)電壓，兩種儀表(biao)之間的(de)區別主要有：

1、連接方式

電流表通常需要與電(dian)(dian)(dian)(dian)(dian)路(lu)串聯使用(yong)，而電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)則(ze)需要與電(dian)(dian)(dian)(dian)(dian)路(lu)并聯。這(zhe)是因(yin)為電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)表(biao)用(yong)于測量電(dian)(dian)(dian)(dian)(dian)路(lu)中的電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)大小(xiao)，而電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)用(yong)于測量電(dian)(dian)(dian)(dian)(dian)路(lu)中的電(dian)(dian)(dian)(dian)(dian)壓(ya)（電(dian)(dian)(dian)(dian)(dian)勢差）。串聯意味著電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)表(biao)位于被測電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的路(lu)徑中，而并聯則(ze)意味著電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)位于電(dian)(dian)(dian)(dian)(dian)路(lu)的兩端，以測量兩點之間的電(dian)(dian)(dian)(dian)(dian)壓(ya)差。

2、測量對象

電(dian)(dian)流表(biao)用于測量(liang)電(dian)(dian)流的(de)大(da)(da)小，而電(dian)(dian)壓表(biao)用于測量(liang)電(dian)(dian)勢差的(de)大(da)(da)小。這意味著電(dian)(dian)流表(biao)關注(zhu)的(de)是通過電(dian)(dian)路(lu)的(de)電(dian)(dian)流強度，而電(dian)(dian)壓表(biao)關注(zhu)的(de)是電(dian)(dian)路(lu)中兩點之間的(de)電(dian)(dian)勢差。

3、量程和內阻

電(dian)(dian)(dian)(dian)流(liu)表(biao)的(de)量程(cheng)通常顯示(shi)為0~0.6A或0~3A，而電(dian)(dian)(dian)(dian)壓表(biao)的(de)量程(cheng)通常顯示(shi)為0~3V和0~6V。電(dian)(dian)(dian)(dian)流(liu)表(biao)的(de)內阻(zu)應(ying)該很小，以便不影響電(dian)(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)(dian)流(liu)，而電(dian)(dian)(dian)(dian)壓表(biao)的(de)內阻(zu)應(ying)該很大，以避免分流(liu)過(guo)多影響電(dian)(dian)(dian)(dian)路的(de)正(zheng)常工作。

二、電流表怎么改成電壓表

電(dian)流表和電(dian)壓表是不(bu)同(tong)的(de)儀表，不(bu)過為了滿足(zu)測(ce)量的(de)要求，有時候可以將(jiang)電(dian)流表改裝成(cheng)電(dian)壓表，具體的(de)方法步驟如下(xia)：

1、計算串(chuan)聯(lian)電(dian)(dian)阻(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)值。利(li)用(yong)歐姆定律(lv)，將(jiang)表頭的(de)滿偏電(dian)(dian)壓除(chu)以(yi)串(chuan)聯(lian)電(dian)(dian)阻(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)值，得(de)到(dao)分壓電(dian)(dian)阻(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)值。

2、調整電流表刻度盤。原來的電流表刻(ke)度(du)盤的(de)每一刻(ke)度(du)數(shu)值需要擴大為原(yuan)來的(de)（Rg+R）倍，即得到改裝(zhuang)后電壓表(biao)的(de)表(biao)盤。

如果想要改裝的電(dian)壓表(biao)量程為(wei)U，則串聯的電(dian)阻R為(wei)：R=U/Ig-rg，其中Ig是表(biao)頭的滿偏電(dian)流，rg是表(biao)頭的內阻。這樣，電(dian)流表(biao)就被(bei)改裝成了電(dian)壓表(biao)，可以測(ce)量更(geng)大(da)的電(dian)壓值。