一、電流表和電壓表有什么區別

電(dian)流表(biao)和(he)電(dian)壓(ya)表(biao)都是電(dian)力領(ling)域應用的測量儀表(biao)，一個(ge)用來(lai)測電(dian)流，一個(ge)用來(lai)測電(dian)壓(ya)，兩種(zhong)儀表(biao)之間的區別主(zhu)要有(you)：

1、連接方式

電流表通(tong)常需(xu)(xu)要與電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)串聯(lian)(lian)使(shi)用，而(er)電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)則需(xu)(xu)要與電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)并聯(lian)(lian)。這是(shi)因為(wei)電(dian)(dian)(dian)(dian)(dian)流表(biao)用于(yu)測(ce)量(liang)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中的(de)電(dian)(dian)(dian)(dian)(dian)流大(da)小，而(er)電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)用于(yu)測(ce)量(liang)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)（電(dian)(dian)(dian)(dian)(dian)勢差）。串聯(lian)(lian)意味著(zhu)電(dian)(dian)(dian)(dian)(dian)流表(biao)位于(yu)被測(ce)電(dian)(dian)(dian)(dian)(dian)流的(de)路(lu)(lu)徑中，而(er)并聯(lian)(lian)則意味著(zhu)電(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)位于(yu)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)兩端，以(yi)測(ce)量(liang)兩點之間(jian)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)差。

2、測量對象

電(dian)(dian)(dian)流(liu)表(biao)用(yong)于測量(liang)電(dian)(dian)(dian)流(liu)的(de)(de)大小，而(er)電(dian)(dian)(dian)壓表(biao)用(yong)于測量(liang)電(dian)(dian)(dian)勢差的(de)(de)大小。這意味(wei)著電(dian)(dian)(dian)流(liu)表(biao)關(guan)注(zhu)的(de)(de)是通過(guo)電(dian)(dian)(dian)路(lu)的(de)(de)電(dian)(dian)(dian)流(liu)強度，而(er)電(dian)(dian)(dian)壓表(biao)關(guan)注(zhu)的(de)(de)是電(dian)(dian)(dian)路(lu)中兩點之間(jian)的(de)(de)電(dian)(dian)(dian)勢差。

3、量程和內阻

電(dian)(dian)流表的(de)(de)(de)(de)(de)(de)量程通常顯示為0~0.6A或0~3A，而電(dian)(dian)壓表的(de)(de)(de)(de)(de)(de)量程通常顯示為0~3V和0~6V。電(dian)(dian)流表的(de)(de)(de)(de)(de)(de)內(nei)阻(zu)應該(gai)(gai)很小，以(yi)便不影響(xiang)電(dian)(dian)路(lu)中的(de)(de)(de)(de)(de)(de)電(dian)(dian)流，而電(dian)(dian)壓表的(de)(de)(de)(de)(de)(de)內(nei)阻(zu)應該(gai)(gai)很大(da)，以(yi)避免分(fen)流過多影響(xiang)電(dian)(dian)路(lu)的(de)(de)(de)(de)(de)(de)正(zheng)常工(gong)作。

二、電流表怎么改成電壓表

電(dian)(dian)流表(biao)和電(dian)(dian)壓表(biao)是不同的儀表(biao)，不過為(wei)了滿(man)足測量的要求，有時候可以將電(dian)(dian)流表(biao)改裝成電(dian)(dian)壓表(biao)，具(ju)體的方(fang)法步驟如下(xia)：

1、計算串聯電阻的(de)(de)阻值。利用歐姆定律，將表(biao)頭的(de)(de)滿偏(pian)電壓(ya)除以串聯電阻的(de)(de)阻值，得到分(fen)壓(ya)電阻的(de)(de)阻值。

2、調整電流表刻度盤。原來的電流表刻(ke)度盤的每(mei)一刻(ke)度數值需要擴大(da)為(wei)原來的（Rg+R）倍，即得到改(gai)裝后電壓表(biao)的表(biao)盤。

如(ru)果想要改(gai)裝的(de)電(dian)(dian)(dian)壓表(biao)量程(cheng)為(wei)U，則串(chuan)聯的(de)電(dian)(dian)(dian)阻R為(wei)：R=U/Ig-rg，其中Ig是表(biao)頭的(de)滿偏電(dian)(dian)(dian)流，rg是表(biao)頭的(de)內阻。這樣(yang)，電(dian)(dian)(dian)流表(biao)就被改(gai)裝成了電(dian)(dian)(dian)壓表(biao)，可(ke)以(yi)測量更大的(de)電(dian)(dian)(dian)壓值。