一、電流表和電壓表有什么區別

電流(liu)表和電壓表都是電力領(ling)域(yu)應用(yong)的(de)(de)測(ce)量(liang)儀(yi)表，一個用(yong)來(lai)(lai)測(ce)電流(liu)，一個用(yong)來(lai)(lai)測(ce)電壓，兩種儀(yi)表之間的(de)(de)區別(bie)主要(yao)有：

1、連接方式

電流表通(tong)常需要與電(dian)(dian)(dian)路(lu)串聯(lian)使用(yong)，而電(dian)(dian)(dian)壓(ya)表(biao)(biao)則需要與電(dian)(dian)(dian)路(lu)并聯(lian)。這是因為電(dian)(dian)(dian)流(liu)表(biao)(biao)用(yong)于測量(liang)電(dian)(dian)(dian)路(lu)中的電(dian)(dian)(dian)流(liu)大小，而電(dian)(dian)(dian)壓(ya)表(biao)(biao)用(yong)于測量(liang)電(dian)(dian)(dian)路(lu)中的電(dian)(dian)(dian)壓(ya)（電(dian)(dian)(dian)勢差）。串聯(lian)意(yi)味(wei)著電(dian)(dian)(dian)流(liu)表(biao)(biao)位(wei)于被(bei)測電(dian)(dian)(dian)流(liu)的路(lu)徑中，而并聯(lian)則意(yi)味(wei)著電(dian)(dian)(dian)壓(ya)表(biao)(biao)位(wei)于電(dian)(dian)(dian)路(lu)的兩(liang)端(duan)，以測量(liang)兩(liang)點之間的電(dian)(dian)(dian)壓(ya)差。

2、測量對象

電(dian)(dian)(dian)(dian)(dian)流表用于(yu)測量電(dian)(dian)(dian)(dian)(dian)流的(de)大小(xiao)，而(er)(er)電(dian)(dian)(dian)(dian)(dian)壓表用于(yu)測量電(dian)(dian)(dian)(dian)(dian)勢差的(de)大小(xiao)。這意味著電(dian)(dian)(dian)(dian)(dian)流表關注的(de)是通過電(dian)(dian)(dian)(dian)(dian)路(lu)的(de)電(dian)(dian)(dian)(dian)(dian)流強度，而(er)(er)電(dian)(dian)(dian)(dian)(dian)壓表關注的(de)是電(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong)兩點之間(jian)的(de)電(dian)(dian)(dian)(dian)(dian)勢差。

3、量程和內阻

電(dian)(dian)(dian)流(liu)表(biao)的(de)量程(cheng)通(tong)(tong)常(chang)(chang)顯示為0~0.6A或0~3A，而電(dian)(dian)(dian)壓表(biao)的(de)量程(cheng)通(tong)(tong)常(chang)(chang)顯示為0~3V和0~6V。電(dian)(dian)(dian)流(liu)表(biao)的(de)內(nei)阻應該很小，以便(bian)不影響(xiang)(xiang)電(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)流(liu)，而電(dian)(dian)(dian)壓表(biao)的(de)內(nei)阻應該很大，以避免分流(liu)過多影響(xiang)(xiang)電(dian)(dian)(dian)路的(de)正常(chang)(chang)工(gong)作。

二、電流表怎么改成電壓表

電(dian)(dian)流(liu)表(biao)(biao)和電(dian)(dian)壓(ya)表(biao)(biao)是不同的儀表(biao)(biao)，不過為了滿足測量的要求(qiu)，有時候可以(yi)將電(dian)(dian)流(liu)表(biao)(biao)改裝成(cheng)電(dian)(dian)壓(ya)表(biao)(biao)，具體的方法步(bu)驟(zou)如下：

1、計算串聯電(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值(zhi)。利用(yong)歐姆定律(lv)，將表頭的(de)滿偏電(dian)(dian)壓(ya)除以串聯電(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值(zhi)，得到(dao)分壓(ya)電(dian)(dian)阻(zu)(zu)的(de)阻(zu)(zu)值(zhi)。

2、調整電流表刻度盤。原來的電流表刻度(du)盤的每一刻度(du)數(shu)值需要擴大(da)為(wei)原來的（Rg+R）倍，即得到改裝后電壓(ya)表的表盤。

如果想(xiang)要改裝的(de)電(dian)壓表(biao)量(liang)程為U，則串聯的(de)電(dian)阻R為：R=U/Ig-rg，其中Ig是(shi)表(biao)頭(tou)的(de)滿偏電(dian)流(liu)，rg是(shi)表(biao)頭(tou)的(de)內阻。這樣，電(dian)流(liu)表(biao)就被改裝成了電(dian)壓表(biao)，可(ke)以測量(liang)更大的(de)電(dian)壓值。