一、電流表和電壓表有什么區別

電(dian)(dian)流(liu)表和電(dian)(dian)壓(ya)(ya)表都是電(dian)(dian)力領域應用(yong)(yong)的測(ce)量儀(yi)表，一個用(yong)(yong)來測(ce)電(dian)(dian)流(liu)，一個用(yong)(yong)來測(ce)電(dian)(dian)壓(ya)(ya)，兩種儀(yi)表之間的區(qu)別主(zhu)要有：

1、連接方式

電流表通常需(xu)要與(yu)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)串聯使用(yong)，而(er)(er)電(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)則需(xu)要與(yu)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)并聯。這是因為電(dian)(dian)(dian)(dian)流表(biao)用(yong)于(yu)測(ce)(ce)量(liang)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中的電(dian)(dian)(dian)(dian)流大小，而(er)(er)電(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)用(yong)于(yu)測(ce)(ce)量(liang)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中的電(dian)(dian)(dian)(dian)壓(ya)(ya)（電(dian)(dian)(dian)(dian)勢差）。串聯意(yi)味(wei)著電(dian)(dian)(dian)(dian)流表(biao)位(wei)于(yu)被測(ce)(ce)電(dian)(dian)(dian)(dian)流的路(lu)(lu)(lu)徑(jing)中，而(er)(er)并聯則意(yi)味(wei)著電(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)位(wei)于(yu)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的兩端，以測(ce)(ce)量(liang)兩點之間的電(dian)(dian)(dian)(dian)壓(ya)(ya)差。

2、測量對象

電流(liu)表用(yong)于(yu)測量電流(liu)的大(da)小，而電壓(ya)表用(yong)于(yu)測量電勢差(cha)的大(da)小。這意味著(zhu)電流(liu)表關(guan)注(zhu)的是通(tong)過電路(lu)(lu)的電流(liu)強(qiang)度(du)，而電壓(ya)表關(guan)注(zhu)的是電路(lu)(lu)中兩(liang)點(dian)之間的電勢差(cha)。

3、量程和內阻

電(dian)(dian)流表(biao)的(de)(de)量程(cheng)通(tong)常(chang)顯(xian)示(shi)為0~0.6A或(huo)0~3A，而電(dian)(dian)壓表(biao)的(de)(de)量程(cheng)通(tong)常(chang)顯(xian)示(shi)為0~3V和(he)0~6V。電(dian)(dian)流表(biao)的(de)(de)內阻應該(gai)很小(xiao)，以便不影響(xiang)電(dian)(dian)路中的(de)(de)電(dian)(dian)流，而電(dian)(dian)壓表(biao)的(de)(de)內阻應該(gai)很大，以避(bi)免分流過多影響(xiang)電(dian)(dian)路的(de)(de)正常(chang)工(gong)作。

二、電流表怎么改成電壓表

電(dian)流表(biao)(biao)和(he)電(dian)壓表(biao)(biao)是不(bu)(bu)同的儀表(biao)(biao)，不(bu)(bu)過為(wei)了滿足測量的要求，有時候可以將(jiang)電(dian)流表(biao)(biao)改(gai)裝成電(dian)壓表(biao)(biao)，具(ju)體的方法步驟如下(xia)：

1、計算串聯(lian)電阻(zu)(zu)的(de)(de)阻(zu)(zu)值(zhi)(zhi)(zhi)。利(li)用歐姆定律，將(jiang)表頭的(de)(de)滿(man)偏(pian)電壓(ya)除以串聯(lian)電阻(zu)(zu)的(de)(de)阻(zu)(zu)值(zhi)(zhi)(zhi)，得到分壓(ya)電阻(zu)(zu)的(de)(de)阻(zu)(zu)值(zhi)(zhi)(zhi)。

2、調整電流表刻度盤。原來的電流表刻度(du)(du)盤的每(mei)一刻度(du)(du)數值(zhi)需要擴大為原來的（Rg+R）倍，即得到改(gai)裝后(hou)電壓(ya)表的表盤。

如果(guo)想(xiang)要改(gai)裝的電(dian)(dian)(dian)(dian)壓表量程為(wei)(wei)U，則串聯的電(dian)(dian)(dian)(dian)阻(zu)R為(wei)(wei)：R=U/Ig-rg，其中(zhong)Ig是(shi)表頭的滿(man)偏電(dian)(dian)(dian)(dian)流，rg是(shi)表頭的內阻(zu)。這樣，電(dian)(dian)(dian)(dian)流表就被改(gai)裝成(cheng)了(le)電(dian)(dian)(dian)(dian)壓表，可以測量更大的電(dian)(dian)(dian)(dian)壓值。