【萬(wan)能(neng)表】萬(wan)能(neng)表的(de)使用方(fang)法(fa) 電工用的萬(wan)能表的使(shi)用方法

一、指針表和數字表的選用：

1、指針表讀取精度較差，但指針擺動的過程比較直觀，其擺動速度幅度有時也能比較客觀地反映了被測量的大小（比如測電視機數據總線（SDL）在傳送數據時的輕微抖動）；數字表讀數直觀，但數字變化的過程看起來很雜亂，不太容易觀看。

2、指針表內一般有兩塊電池，一塊低電壓的1.5V，一塊是高電壓的9V或15V，其黑表筆相對紅表筆來說是正端。數字表則常用一塊6V或9V的電池。在(zai)電(dian)阻檔，指針表(biao)的表(biao)筆輸出(chu)(chu)電(dian)流(liu)相(xiang)對數字表(biao)來說要大(da)很(hen)多，用(yong)R×1Ω檔可以(yi)使揚聲器發(fa)出(chu)(chu)響亮的“噠(da)”聲，用(yong)R×10kΩ檔甚至可以(yi)點亮發(fa)光二極管（LED）。

3、在電(dian)(dian)壓檔(dang)(dang)，指針(zhen)表(biao)內(nei)(nei)阻相對(dui)數(shu)字(zi)表(biao)來說(shuo)比(bi)較小(xiao)，測量精(jing)度相比(bi)較差。某些高電(dian)(dian)壓微(wei)電(dian)(dian)流的(de)場合(he)甚至無法測準(zhun)，因(yin)為(wei)其內(nei)(nei)阻會對(dui)被(bei)測電(dian)(dian)路造成(cheng)影(ying)響（比(bi)如(ru)在測電(dian)(dian)視機顯(xian)像管的(de)加速(su)級(ji)電(dian)(dian)壓時(shi)測量值會比(bi)實際值低很(hen)多）。數(shu)字(zi)表(biao)電(dian)(dian)壓檔(dang)(dang)的(de)內(nei)(nei)阻很(hen)大(da)，至少在兆歐級(ji)，對(dui)被(bei)測電(dian)(dian)路影(ying)響很(hen)小(xiao)。但極高的(de)輸出阻抗使其易受(shou)感應(ying)電(dian)(dian)壓的(de)影(ying)響，在一些電(dian)(dian)磁干擾比(bi)較強的(de)場合(he)測出的(de)數(shu)據可能是虛的(de)。

4、總(zong)之，在相對(dui)來(lai)說大電(dian)(dian)(dian)流(liu)高電(dian)(dian)(dian)壓的模擬電(dian)(dian)(dian)路(lu)測量中適用指(zhi)(zhi)針表(biao)，比如(ru)電(dian)(dian)(dian)視(shi)機(ji)、音響功放。在低(di)電(dian)(dian)(dian)壓小電(dian)(dian)(dian)流(liu)的數字電(dian)(dian)(dian)路(lu)測量中適用數字表(biao)，比如(ru)BP機(ji)、手機(ji)等。不(bu)是絕(jue)對(dui)的，可(ke)根據情況選(xuan)用指(zhi)(zhi)針表(biao)和數字表(biao)。

二、測量技巧（如不作說明，則指用的是指針表）：

1、測喇叭、耳機、動圈式(shi)話筒：用(yong)R×1Ω檔，任一表筆(bi)接一端，另(ling)一表筆(bi)點(dian)觸(chu)另(ling)一端，正常時會(hui)發出(chu)清脆響量的“噠(da)”聲。如(ru)果不(bu)響，則(ze)是(shi)線圈斷了(le)，如(ru)果響聲小而(er)尖，則(ze)是(shi)有擦圈問題，也不(bu)能用(yong)。

2、測(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)：用電(dian)(dian)(dian)阻(zu)檔(dang)，根據(ju)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)選(xuan)擇適當的(de)(de)量(liang)(liang)(liang)程，并注意測(ce)量(liang)(liang)(liang)時(shi)(shi)對(dui)于電(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)黑表筆要接(jie)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)正極。①、估(gu)(gu)測(ce)微(wei)波法級電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)的(de)(de)大(da)(da)小：可(ke)(ke)(ke)(ke)憑經驗或(huo)(huo)參(can)(can)照相(xiang)同容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)的(de)(de)標準電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)，根據(ju)指(zhi)針(zhen)擺(bai)動的(de)(de)最(zui)大(da)(da)幅(fu)度(du)來判定。所(suo)參(can)(can)照的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)不(bu)必耐壓值也一(yi)(yi)樣，只(zhi)要容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)相(xiang)同即(ji)可(ke)(ke)(ke)(ke)，例如(ru)估(gu)(gu)測(ce)一(yi)(yi)個(ge)100μF/250V的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)可(ke)(ke)(ke)(ke)用一(yi)(yi)個(ge)100μF/25V的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)來參(can)(can)照，只(zhi)要它們指(zhi)針(zhen)擺(bai)動最(zui)大(da)(da)幅(fu)度(du)一(yi)(yi)樣，即(ji)可(ke)(ke)(ke)(ke)斷定容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)一(yi)(yi)樣。②、估(gu)(gu)測(ce)皮法級電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)大(da)(da)小：要用R×10kΩ檔(dang)，但只(zhi)能測(ce)到1000pF以上的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)。對(dui)1000pF或(huo)(huo)稍大(da)(da)一(yi)(yi)點(dian)的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)，只(zhi)要表針(zhen)稍有擺(bai)動，即(ji)可(ke)(ke)(ke)(ke)認為容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)夠了。③、測(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)是否漏電(dian)(dian)(dian)：對(dui)一(yi)(yi)千(qian)微(wei)法以上的(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)，可(ke)(ke)(ke)(ke)先用R×10Ω檔(dang)將其快速充電(dian)(dian)(dian)，并初步估(gu)(gu)測(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)，然后改(gai)到R×1kΩ檔(dang)繼(ji)續(xu)測(ce)一(yi)(yi)會兒，這時(shi)(shi)指(zhi)針(zhen)不(bu)應回返(fan)，而應停在或(huo)(huo)十(shi)分接(jie)近∞處(chu)，否則就(jiu)是有漏電(dian)(dian)(dian)現(xian)象(xiang)。對(dui)一(yi)(yi)些幾(ji)十(shi)微(wei)法以下的(de)(de)定時(shi)(shi)或(huo)(huo)振蕩(dang)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)（比如(ru)彩電(dian)(dian)(dian)開關(guan)電(dian)(dian)(dian)源的(de)(de)振蕩(dang)電(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)），對(dui)其漏電(dian)(dian)(dian)特(te)性(xing)要求非(fei)常高，只(zhi)要稍有漏電(dian)(dian)(dian)就(jiu)不(bu)能用，這時(shi)(shi)可(ke)(ke)(ke)(ke)在R×1kΩ檔(dang)充完(wan)電(dian)(dian)(dian)后再改(gai)用R×10kΩ檔(dang)繼(ji)續(xu)測(ce)量(liang)(liang)(liang)，同樣表針(zhen)應停在∞處(chu)而不(bu)應回返(fan)。

3、在(zai)(zai)(zai)(zai)(zai)路(lu)測(ce)(ce)(ce)二(er)極管(guan)、三極管(guan)、穩(wen)壓管(guan)好壞(huai)(huai)：因為在(zai)(zai)(zai)(zai)(zai)實(shi)(shi)際電路(lu)中，三極管(guan)的(de)(de)偏置電阻(zu)(zu)或(huo)二(er)極管(guan)、穩(wen)壓管(guan)的(de)(de)周(zhou)邊電阻(zu)(zu)一般都比較大(da)，大(da)都在(zai)(zai)(zai)(zai)(zai)幾(ji)百(bai)幾(ji)千(qian)歐姆以(yi)上，這樣，我們就可(ke)(ke)(ke)以(yi)用(yong)(yong)萬用(yong)(yong)表(biao)的(de)(de)R×10Ω或(huo)R×1Ω檔(dang)來(lai)在(zai)(zai)(zai)(zai)(zai)路(lu)測(ce)(ce)(ce)量(liang)PN結(jie)的(de)(de)好壞(huai)(huai)。在(zai)(zai)(zai)(zai)(zai)路(lu)測(ce)(ce)(ce)量(liang)時(shi)(shi)，用(yong)(yong)R×10Ω檔(dang)測(ce)(ce)(ce)PN結(jie)應有(you)較明(ming)顯(xian)的(de)(de)正反向(xiang)特性(xing)（如果(guo)正反向(xiang)電阻(zu)(zu)相差不(bu)太(tai)明(ming)顯(xian)，可(ke)(ke)(ke)改用(yong)(yong)R×1Ω檔(dang)來(lai)測(ce)(ce)(ce)），一般正向(xiang)電阻(zu)(zu)在(zai)(zai)(zai)(zai)(zai)R×10Ω檔(dang)測(ce)(ce)(ce)時(shi)(shi)表(biao)針(zhen)應指示在(zai)(zai)(zai)(zai)(zai)200Ω左右(you)(you)，在(zai)(zai)(zai)(zai)(zai)R×1Ω檔(dang)測(ce)(ce)(ce)時(shi)(shi)表(biao)針(zhen)應指示在(zai)(zai)(zai)(zai)(zai)30Ω左右(you)(you)（根據不(bu)同(tong)表(biao)型可(ke)(ke)(ke)能(neng)略有(you)出入）。如果(guo)測(ce)(ce)(ce)量(liang)結(jie)果(guo)正向(xiang)阻(zu)(zu)值(zhi)太(tai)大(da)或(huo)反向(xiang)阻(zu)(zu)值(zhi)太(tai)小(xiao)，都說明(ming)這個(ge)PN結(jie)有(you)問題，這個(ge)管(guan)子(zi)也就有(you)問題了。這種方法對于維修時(shi)(shi)特別有(you)效，可(ke)(ke)(ke)以(yi)非常快速地找出壞(huai)(huai)管(guan)，甚至可(ke)(ke)(ke)以(yi)測(ce)(ce)(ce)出尚(shang)未完(wan)全壞(huai)(huai)掉但特性(xing)變壞(huai)(huai)的(de)(de)管(guan)子(zi)。比如當你用(yong)(yong)小(xiao)阻(zu)(zu)值(zhi)檔(dang)測(ce)(ce)(ce)量(liang)某個(ge)PN結(jie)正向(xiang)電阻(zu)(zu)過大(da)，如果(guo)你把(ba)它焊下來(lai)用(yong)(yong)常用(yong)(yong)的(de)(de)R×1kΩ檔(dang)再測(ce)(ce)(ce)，可(ke)(ke)(ke)能(neng)還(huan)是正常的(de)(de)，其實(shi)(shi)這個(ge)管(guan)子(zi)的(de)(de)特性(xing)已經變壞(huai)(huai)了，不(bu)能(neng)正常工作或(huo)不(bu)穩(wen)定了。

4、測(ce)(ce)電阻(zu)：重要的是要選好量(liang)程(cheng)，當(dang)指(zhi)針指(zhi)示于1/3～2/3滿量(liang)程(cheng)時測(ce)(ce)量(liang)精度最(zui)高，讀(du)數最(zui)準(zhun)確(que)。要注意的是，在用R×10k電阻(zu)檔(dang)測(ce)(ce)兆歐級的大阻(zu)值電阻(zu)時，不可將(jiang)手(shou)指(zhi)捏(nie)在電阻(zu)兩端，這樣人(ren)體(ti)電阻(zu)會使測(ce)(ce)量(liang)結(jie)果(guo)偏小。

5、測(ce)(ce)(ce)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)二極管(guan)(guan)：我們通常(chang)所(suo)用到的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值一(yi)般(ban)都大(da)于1.5V，而指(zhi)(zhi)針表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)(de)(de)R×1k以(yi)下的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)阻檔是(shi)用表(biao)(biao)(biao)(biao)內的(de)(de)(de)(de)(de)(de)(de)1.5V電(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)，這(zhe)樣(yang)(yang)，用R×1k以(yi)下的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)阻檔測(ce)(ce)(ce)量(liang)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)就如(ru)同(tong)測(ce)(ce)(ce)二極管(guan)(guan)一(yi)樣(yang)(yang)，具有(you)完(wan)全(quan)的(de)(de)(de)(de)(de)(de)(de)單向導電(dian)(dian)(dian)性。但(dan)指(zhi)(zhi)針表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)(de)(de)R×10k檔是(shi)用9V或(huo)15V電(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)，在用R×10k測(ce)(ce)(ce)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值小于9V或(huo)15V的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)時，反向阻值就不(bu)會是(shi)∞，而是(shi)有(you)一(yi)定阻值，但(dan)這(zhe)個阻值還是(shi)要(yao)大(da)大(da)高于穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)正(zheng)向阻值的(de)(de)(de)(de)(de)(de)(de)。如(ru)此(ci)，我們就可(ke)(ke)以(yi)初步估測(ce)(ce)(ce)出(chu)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)好壞。但(dan)是(shi)，好的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)還要(yao)有(you)個準(zhun)確的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值，業(ye)余條件下怎么(me)估測(ce)(ce)(ce)出(chu)這(zhe)個穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值呢？不(bu)難，再去找一(yi)塊(kuai)指(zhi)(zhi)針表(biao)(biao)(biao)(biao)來(lai)就可(ke)(ke)以(yi)了。方法(fa)是(shi)：先將(jiang)(jiang)一(yi)塊(kuai)表(biao)(biao)(biao)(biao)置(zhi)于R×10k檔，其黑、紅(hong)表(biao)(biao)(biao)(biao)筆分(fen)別(bie)接在穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)陰極和陽極，這(zhe)時就模擬(ni)出(chu)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)實際(ji)工作狀態，再取另一(yi)塊(kuai)表(biao)(biao)(biao)(biao)置(zhi)于電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)檔V×10V或(huo)V×50V（根據(ju)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值）上，將(jiang)(jiang)紅(hong)、黑表(biao)(biao)(biao)(biao)筆分(fen)別(bie)搭接到剛才那塊(kuai)表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)(de)(de)的(de)(de)(de)(de)(de)(de)(de)黑、紅(hong)表(biao)(biao)(biao)(biao)筆上，這(zhe)時測(ce)(ce)(ce)出(chu)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值就基本(ben)(ben)上是(shi)這(zhe)個穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值。說“基本(ben)(ben)上”，是(shi)因為第一(yi)塊(kuai)表(biao)(biao)(biao)(biao)對穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)偏(pian)置(zhi)電(dian)(dian)(dian)流相(xiang)對正(zheng)常(chang)使用時的(de)(de)(de)(de)(de)(de)(de)偏(pian)置(zhi)電(dian)(dian)(dian)流稍小些(xie)，所(suo)以(yi)測(ce)(ce)(ce)出(chu)的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值會稍偏(pian)大(da)一(yi)點，但(dan)基本(ben)(ben)相(xiang)差不(bu)大(da)。這(zhe)個方法(fa)只(zhi)可(ke)(ke)估測(ce)(ce)(ce)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值小于指(zhi)(zhi)針表(biao)(biao)(biao)(biao)高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)。如(ru)果(guo)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)(de)(de)穩(wen)(wen)(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)值太高，就只(zhi)能用外加電(dian)(dian)(dian)源(yuan)的(de)(de)(de)(de)(de)(de)(de)方法(fa)來(lai)測(ce)(ce)(ce)量(liang)了（這(zhe)樣(yang)(yang)看來(lai)，我們在選用指(zhi)(zhi)針表(biao)(biao)(biao)(biao)時，選用高壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)(ya)(ya)為15V的(de)(de)(de)(de)(de)(de)(de)要(yao)比9V的(de)(de)(de)(de)(de)(de)(de)更適用些(xie)）。

6、測(ce)三(san)極管(guan)(guan)(guan)(guan)(guan)(guan)：通常我們要用R×1kΩ檔(dang)，不(bu)管(guan)(guan)(guan)(guan)(guan)(guan)是(shi)(shi)(shi)(shi)NPN管(guan)(guan)(guan)(guan)(guan)(guan)還(huan)(huan)是(shi)(shi)(shi)(shi)PNP管(guan)(guan)(guan)(guan)(guan)(guan)，不(bu)管(guan)(guan)(guan)(guan)(guan)(guan)是(shi)(shi)(shi)(shi)小功率、中功率、大(da)(da)(da)(da)(da)功率管(guan)(guan)(guan)(guan)(guan)(guan)，測(ce)其(qi)(qi)be結cb結都(dou)應(ying)(ying)呈現(xian)與(yu)二極管(guan)(guan)(guan)(guan)(guan)(guan)完全相(xiang)同(tong)(tong)的(de)(de)(de)(de)(de)單向(xiang)(xiang)(xiang)導電(dian)(dian)性，反(fan)(fan)(fan)向(xiang)(xiang)(xiang)電(dian)(dian)阻(zu)無窮大(da)(da)(da)(da)(da)，其(qi)(qi)正(zheng)向(xiang)(xiang)(xiang)電(dian)(dian)阻(zu)大(da)(da)(da)(da)(da)約(yue)在10K左(zuo)右(you)(you)。為(wei)進(jin)一步估(gu)測(ce)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)特性的(de)(de)(de)(de)(de)好壞(huai)，必要時(shi)(shi)還(huan)(huan)應(ying)(ying)變換電(dian)(dian)阻(zu)檔(dang)位(wei)進(jin)行多次測(ce)量(liang)，方法是(shi)(shi)(shi)(shi)：置R×10Ω檔(dang)測(ce)PN結正(zheng)向(xiang)(xiang)(xiang)導通電(dian)(dian)阻(zu)都(dou)在大(da)(da)(da)(da)(da)約(yue)200Ω左(zuo)右(you)(you)；置R×1Ω檔(dang)測(ce)PN結正(zheng)向(xiang)(xiang)(xiang)導通電(dian)(dian)阻(zu)都(dou)在大(da)(da)(da)(da)(da)約(yue)30Ω左(zuo)右(you)(you)，（以(yi)(yi)上為(wei)47型(xing)(xing)表(biao)(biao)(biao)測(ce)得數據，其(qi)(qi)它(ta)型(xing)(xing)號表(biao)(biao)(biao)大(da)(da)(da)(da)(da)概(gai)略有(you)不(bu)同(tong)(tong)，可(ke)多試測(ce)幾個好管(guan)(guan)(guan)(guan)(guan)(guan)總結一下(xia)，做到心中有(you)數）如果讀(du)數偏(pian)(pian)大(da)(da)(da)(da)(da)太多，可(ke)以(yi)(yi)斷定管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)的(de)(de)(de)(de)(de)特性不(bu)好。還(huan)(huan)可(ke)將表(biao)(biao)(biao)置于R×10kΩ再測(ce)，耐壓(ya)再低(di)的(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)（基本上三(san)極管(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)耐壓(ya)都(dou)在30V以(yi)(yi)上），其(qi)(qi)cb結反(fan)(fan)(fan)向(xiang)(xiang)(xiang)電(dian)(dian)阻(zu)也(ye)應(ying)(ying)在∞，但(dan)其(qi)(qi)be結的(de)(de)(de)(de)(de)反(fan)(fan)(fan)向(xiang)(xiang)(xiang)電(dian)(dian)阻(zu)可(ke)能會有(you)些，表(biao)(biao)(biao)針(zhen)會稍有(you)偏(pian)(pian)轉(zhuan)（一般不(bu)會超過(guo)滿量(liang)程的(de)(de)(de)(de)(de)1/3，根據管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)的(de)(de)(de)(de)(de)耐壓(ya)不(bu)同(tong)(tong)而(er)不(bu)同(tong)(tong)）。同(tong)(tong)樣，在用R×10kΩ檔(dang)測(ce)ec間(jian)(jian)(對(dui)NPN管(guan)(guan)(guan)(guan)(guan)(guan)）或ce間(jian)(jian)（對(dui)PNP管(guan)(guan)(guan)(guan)(guan)(guan)）的(de)(de)(de)(de)(de)電(dian)(dian)阻(zu)時(shi)(shi)，表(biao)(biao)(biao)針(zhen)可(ke)能略有(you)偏(pian)(pian)轉(zhuan)，但(dan)這(zhe)不(bu)表(biao)(biao)(biao)示管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)是(shi)(shi)(shi)(shi)壞(huai)的(de)(de)(de)(de)(de)。但(dan)在用R×1kΩ以(yi)(yi)下(xia)檔(dang)測(ce)ce或ec間(jian)(jian)電(dian)(dian)阻(zu)時(shi)(shi)，表(biao)(biao)(biao)頭指示應(ying)(ying)為(wei)無窮大(da)(da)(da)(da)(da)，否則管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)就是(shi)(shi)(shi)(shi)有(you)問(wen)題。應(ying)(ying)該說(shuo)明(ming)一點的(de)(de)(de)(de)(de)是(shi)(shi)(shi)(shi)，以(yi)(yi)上測(ce)量(liang)是(shi)(shi)(shi)(shi)針(zhen)對(dui)硅管(guan)(guan)(guan)(guan)(guan)(guan)而(er)言的(de)(de)(de)(de)(de)，對(dui)鍺管(guan)(guan)(guan)(guan)(guan)(guan)不(bu)適用。不(bu)過(guo)現(xian)在鍺管(guan)(guan)(guan)(guan)(guan)(guan)也(ye)很(hen)少(shao)見了。另外，所(suo)說(shuo)的(de)(de)(de)(de)(de)“反(fan)(fan)(fan)向(xiang)(xiang)(xiang)”是(shi)(shi)(shi)(shi)針(zhen)對(dui)PN結而(er)言，對(dui)NPN管(guan)(guan)(guan)(guan)(guan)(guan)和PNP管(guan)(guan)(guan)(guan)(guan)(guan)方向(xiang)(xiang)(xiang)實際上是(shi)(shi)(shi)(shi)不(bu)同(tong)(tong)的(de)(de)(de)(de)(de)。