一、電流表和電壓表有什么區別

電(dian)流表(biao)和電(dian)壓表(biao)都是電(dian)力領域應用的(de)(de)測量儀表(biao)，一(yi)個用來測電(dian)流，一(yi)個用來測電(dian)壓，兩種儀表(biao)之間的(de)(de)區(qu)別主要有：

1、連接方式

電流表通(tong)常(chang)需(xu)(xu)要與電(dian)(dian)(dian)(dian)(dian)路串聯(lian)使(shi)用(yong)，而電(dian)(dian)(dian)(dian)(dian)壓表(biao)(biao)(biao)(biao)則需(xu)(xu)要與電(dian)(dian)(dian)(dian)(dian)路并聯(lian)。這(zhe)是因為電(dian)(dian)(dian)(dian)(dian)流表(biao)(biao)(biao)(biao)用(yong)于測(ce)量電(dian)(dian)(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)(dian)(dian)流大小(xiao)，而電(dian)(dian)(dian)(dian)(dian)壓表(biao)(biao)(biao)(biao)用(yong)于測(ce)量電(dian)(dian)(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)(dian)(dian)壓（電(dian)(dian)(dian)(dian)(dian)勢(shi)差）。串聯(lian)意味(wei)著(zhu)電(dian)(dian)(dian)(dian)(dian)流表(biao)(biao)(biao)(biao)位于被測(ce)電(dian)(dian)(dian)(dian)(dian)流的(de)路徑中，而并聯(lian)則意味(wei)著(zhu)電(dian)(dian)(dian)(dian)(dian)壓表(biao)(biao)(biao)(biao)位于電(dian)(dian)(dian)(dian)(dian)路的(de)兩端，以測(ce)量兩點之間(jian)的(de)電(dian)(dian)(dian)(dian)(dian)壓差。

2、測量對象

電(dian)(dian)流(liu)(liu)表(biao)用于測量電(dian)(dian)流(liu)(liu)的大(da)(da)小，而電(dian)(dian)壓表(biao)用于測量電(dian)(dian)勢差的大(da)(da)小。這(zhe)意味(wei)著電(dian)(dian)流(liu)(liu)表(biao)關注的是(shi)(shi)通過電(dian)(dian)路的電(dian)(dian)流(liu)(liu)強度(du)，而電(dian)(dian)壓表(biao)關注的是(shi)(shi)電(dian)(dian)路中兩點之間的電(dian)(dian)勢差。

3、量程和內阻

電(dian)(dian)(dian)(dian)流表(biao)(biao)的(de)量程(cheng)(cheng)通(tong)(tong)常(chang)顯示(shi)為(wei)0~0.6A或0~3A，而電(dian)(dian)(dian)(dian)壓表(biao)(biao)的(de)量程(cheng)(cheng)通(tong)(tong)常(chang)顯示(shi)為(wei)0~3V和0~6V。電(dian)(dian)(dian)(dian)流表(biao)(biao)的(de)內阻應該很小，以便(bian)不(bu)影(ying)響(xiang)電(dian)(dian)(dian)(dian)路中的(de)電(dian)(dian)(dian)(dian)流，而電(dian)(dian)(dian)(dian)壓表(biao)(biao)的(de)內阻應該很大(da)，以避(bi)免分流過多影(ying)響(xiang)電(dian)(dian)(dian)(dian)路的(de)正常(chang)工作。

二、電流表怎么改成電壓表

電(dian)流表(biao)和電(dian)壓(ya)(ya)表(biao)是(shi)不同的儀表(biao)，不過(guo)為了滿足測量的要求(qiu)，有時候可以將(jiang)電(dian)流表(biao)改裝成電(dian)壓(ya)(ya)表(biao)，具體的方法步(bu)驟如下：

1、計算(suan)串(chuan)聯(lian)電阻(zu)的阻(zu)值。利用歐姆定律，將表(biao)頭的滿(man)偏電壓除以串(chuan)聯(lian)電阻(zu)的阻(zu)值，得到分壓電阻(zu)的阻(zu)值。

2、調整電流表刻度盤。原來的電流表刻(ke)度盤的每一(yi)刻(ke)度數值需要擴(kuo)大為原來的（Rg+R）倍(bei)，即(ji)得到改(gai)裝后電壓表的表盤。

如(ru)果想要改裝(zhuang)的電(dian)壓表量程為U，則串聯的電(dian)阻R為：R=U/Ig-rg，其中Ig是表頭的滿偏電(dian)流，rg是表頭的內阻。這(zhe)樣，電(dian)流表就被改裝(zhuang)成了電(dian)壓表，可以測(ce)量更大的電(dian)壓值(zhi)。