【萬(wan)能表(biao)】萬(wan)能表(biao)的使用方法(fa) 電工用的萬能(neng)表的使(shi)用方法(fa)

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。在電(dian)阻檔(dang)，指針表(biao)的表(biao)筆輸出電(dian)流相對數字(zi)表(biao)來說要(yao)大很多，用(yong)R×1Ω檔(dang)可(ke)(ke)以使揚(yang)聲器發(fa)出響亮的“噠(da)”聲，用(yong)R×10kΩ檔(dang)甚至可(ke)(ke)以點亮發(fa)光二(er)極管(guan)（LED）。

3、在(zai)電壓(ya)(ya)檔，指(zhi)針表(biao)內阻(zu)相對數(shu)字(zi)表(biao)來說比較(jiao)小，測(ce)(ce)量精度相比較(jiao)差。某些(xie)高電壓(ya)(ya)微電流的(de)場合甚至(zhi)(zhi)無法測(ce)(ce)準(zhun)，因為其內阻(zu)會(hui)對被(bei)測(ce)(ce)電路(lu)造成影響（比如在(zai)測(ce)(ce)電視機顯像管的(de)加速級電壓(ya)(ya)時測(ce)(ce)量值(zhi)會(hui)比實(shi)際值(zhi)低很多）。數(shu)字(zi)表(biao)電壓(ya)(ya)檔的(de)內阻(zu)很大，至(zhi)(zhi)少在(zai)兆歐(ou)級，對被(bei)測(ce)(ce)電路(lu)影響很小。但極高的(de)輸出阻(zu)抗使其易受(shou)感應(ying)電壓(ya)(ya)的(de)影響，在(zai)一些(xie)電磁(ci)干(gan)擾比較(jiao)強的(de)場合測(ce)(ce)出的(de)數(shu)據可能是(shi)虛(xu)的(de)。

4、總之，在相對來說大電(dian)(dian)(dian)流高電(dian)(dian)(dian)壓(ya)的模擬電(dian)(dian)(dian)路(lu)測量中適用指(zhi)針表，比如電(dian)(dian)(dian)視機(ji)、音響(xiang)功放。在低電(dian)(dian)(dian)壓(ya)小(xiao)電(dian)(dian)(dian)流的數字(zi)(zi)電(dian)(dian)(dian)路(lu)測量中適用數字(zi)(zi)表，比如BP機(ji)、手機(ji)等(deng)。不是絕對的，可(ke)根據情(qing)況選用指(zhi)針表和(he)數字(zi)(zi)表。

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(quan)式(shi)話(hua)筒：用R×1Ω檔(dang)，任一(yi)(yi)表筆接(jie)一(yi)(yi)端，另(ling)一(yi)(yi)表筆點觸(chu)另(ling)一(yi)(yi)端，正常時(shi)會(hui)發出清(qing)脆(cui)響(xiang)量的“噠”聲。如(ru)果不(bu)響(xiang)，則(ze)是(shi)(shi)線圈(quan)斷了，如(ru)果響(xiang)聲小而尖，則(ze)是(shi)(shi)有擦圈(quan)問(wen)題(ti)，也不(bu)能用。

2、測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)：用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)阻檔(dang)(dang)，根(gen)(gen)據(ju)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)選擇適當(dang)的(de)(de)量(liang)(liang)(liang)(liang)(liang)程，并注意(yi)測(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)時(shi)(shi)對于電(dian)(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)黑表筆要接(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)正極。①、估測(ce)(ce)(ce)微波(bo)法(fa)級(ji)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)的(de)(de)大(da)小：可(ke)(ke)憑經驗或參(can)照相同容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)的(de)(de)標準電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，根(gen)(gen)據(ju)指針(zhen)擺動的(de)(de)最大(da)幅(fu)度來判定。所參(can)照的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)不(bu)(bu)(bu)必耐壓(ya)值也(ye)一(yi)(yi)樣(yang)，只要容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)相同即可(ke)(ke)，例(li)如估測(ce)(ce)(ce)一(yi)(yi)個(ge)100μF/250V的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)可(ke)(ke)用(yong)一(yi)(yi)個(ge)100μF/25V的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)來參(can)照，只要它們(men)指針(zhen)擺動最大(da)幅(fu)度一(yi)(yi)樣(yang)，即可(ke)(ke)斷定容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)一(yi)(yi)樣(yang)。②、估測(ce)(ce)(ce)皮法(fa)級(ji)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)大(da)小：要用(yong)R×10kΩ檔(dang)(dang)，但只能(neng)測(ce)(ce)(ce)到1000pF以上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)。對1000pF或稍大(da)一(yi)(yi)點的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，只要表針(zhen)稍有(you)(you)擺動，即可(ke)(ke)認為容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)夠了。③、測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)是否(fou)漏電(dian)(dian)(dian)(dian)(dian)(dian)：對一(yi)(yi)千(qian)微法(fa)以上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，可(ke)(ke)先用(yong)R×10Ω檔(dang)(dang)將其快速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，并初步估測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)量(liang)(liang)(liang)(liang)(liang)，然后改(gai)到R×1kΩ檔(dang)(dang)繼(ji)(ji)續測(ce)(ce)(ce)一(yi)(yi)會兒，這(zhe)時(shi)(shi)指針(zhen)不(bu)(bu)(bu)應(ying)回返，而應(ying)停(ting)在(zai)或十分接(jie)(jie)近∞處，否(fou)則就是有(you)(you)漏電(dian)(dian)(dian)(dian)(dian)(dian)現象。對一(yi)(yi)些幾十微法(fa)以下的(de)(de)定時(shi)(shi)或振蕩(dang)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)（比如彩電(dian)(dian)(dian)(dian)(dian)(dian)開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)振蕩(dang)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)），對其漏電(dian)(dian)(dian)(dian)(dian)(dian)特性要求(qiu)非常高，只要稍有(you)(you)漏電(dian)(dian)(dian)(dian)(dian)(dian)就不(bu)(bu)(bu)能(neng)用(yong)，這(zhe)時(shi)(shi)可(ke)(ke)在(zai)R×1kΩ檔(dang)(dang)充(chong)(chong)完電(dian)(dian)(dian)(dian)(dian)(dian)后再(zai)改(gai)用(yong)R×10kΩ檔(dang)(dang)繼(ji)(ji)續測(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)，同樣(yang)表針(zhen)應(ying)停(ting)在(zai)∞處而不(bu)(bu)(bu)應(ying)回返。

3、在(zai)(zai)路(lu)(lu)測(ce)(ce)(ce)(ce)二極(ji)管(guan)(guan)(guan)、三極(ji)管(guan)(guan)(guan)、穩壓(ya)管(guan)(guan)(guan)好壞(huai)(huai)：因為在(zai)(zai)實(shi)際電路(lu)(lu)中，三極(ji)管(guan)(guan)(guan)的(de)(de)(de)偏置電阻或二極(ji)管(guan)(guan)(guan)、穩壓(ya)管(guan)(guan)(guan)的(de)(de)(de)周邊電阻一般(ban)(ban)都(dou)比較大(da)，大(da)都(dou)在(zai)(zai)幾百幾千歐姆以上，這(zhe)樣，我們(men)就可(ke)(ke)以用(yong)萬(wan)用(yong)表的(de)(de)(de)R×10Ω或R×1Ω檔(dang)(dang)來(lai)在(zai)(zai)路(lu)(lu)測(ce)(ce)(ce)(ce)量PN結(jie)的(de)(de)(de)好壞(huai)(huai)。在(zai)(zai)路(lu)(lu)測(ce)(ce)(ce)(ce)量時(shi)(shi)(shi)，用(yong)R×10Ω檔(dang)(dang)測(ce)(ce)(ce)(ce)PN結(jie)應有(you)(you)(you)較明顯(xian)(xian)的(de)(de)(de)正反向(xiang)特性(xing)（如(ru)(ru)果(guo)(guo)正反向(xiang)電阻相差不(bu)太(tai)明顯(xian)(xian)，可(ke)(ke)改用(yong)R×1Ω檔(dang)(dang)來(lai)測(ce)(ce)(ce)(ce)），一般(ban)(ban)正向(xiang)電阻在(zai)(zai)R×10Ω檔(dang)(dang)測(ce)(ce)(ce)(ce)時(shi)(shi)(shi)表針應指(zhi)(zhi)示在(zai)(zai)200Ω左(zuo)右，在(zai)(zai)R×1Ω檔(dang)(dang)測(ce)(ce)(ce)(ce)時(shi)(shi)(shi)表針應指(zhi)(zhi)示在(zai)(zai)30Ω左(zuo)右（根據不(bu)同表型可(ke)(ke)能略有(you)(you)(you)出(chu)入）。如(ru)(ru)果(guo)(guo)測(ce)(ce)(ce)(ce)量結(jie)果(guo)(guo)正向(xiang)阻值(zhi)(zhi)太(tai)大(da)或反向(xiang)阻值(zhi)(zhi)太(tai)小(xiao)，都(dou)說明這(zhe)個PN結(jie)有(you)(you)(you)問題，這(zhe)個管(guan)(guan)(guan)子(zi)也就有(you)(you)(you)問題了(le)。這(zhe)種(zhong)方(fang)法對于維修時(shi)(shi)(shi)特別有(you)(you)(you)效，可(ke)(ke)以非常(chang)(chang)快速(su)地找(zhao)出(chu)壞(huai)(huai)管(guan)(guan)(guan)，甚(shen)至(zhi)可(ke)(ke)以測(ce)(ce)(ce)(ce)出(chu)尚(shang)未完全壞(huai)(huai)掉(diao)但特性(xing)變壞(huai)(huai)的(de)(de)(de)管(guan)(guan)(guan)子(zi)。比如(ru)(ru)當你(ni)用(yong)小(xiao)阻值(zhi)(zhi)檔(dang)(dang)測(ce)(ce)(ce)(ce)量某個PN結(jie)正向(xiang)電阻過大(da)，如(ru)(ru)果(guo)(guo)你(ni)把它焊下來(lai)用(yong)常(chang)(chang)用(yong)的(de)(de)(de)R×1kΩ檔(dang)(dang)再測(ce)(ce)(ce)(ce)，可(ke)(ke)能還是(shi)正常(chang)(chang)的(de)(de)(de)，其實(shi)這(zhe)個管(guan)(guan)(guan)子(zi)的(de)(de)(de)特性(xing)已經變壞(huai)(huai)了(le)，不(bu)能正常(chang)(chang)工作或不(bu)穩定了(le)。

4、測(ce)電阻(zu)(zu)(zu)：重要的(de)(de)(de)是(shi)要選好量(liang)程，當指針(zhen)指示(shi)于1/3～2/3滿量(liang)程時測(ce)量(liang)精(jing)度最高，讀數最準確(que)。要注意的(de)(de)(de)是(shi)，在用R×10k電阻(zu)(zu)(zu)檔測(ce)兆歐(ou)級的(de)(de)(de)大阻(zu)(zu)(zu)值(zhi)電阻(zu)(zu)(zu)時，不可(ke)將手指捏(nie)在電阻(zu)(zu)(zu)兩端，這樣人體電阻(zu)(zu)(zu)會(hui)使測(ce)量(liang)結果偏小。

5、測(ce)(ce)(ce)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)二極(ji)管(guan)：我(wo)(wo)們(men)通常(chang)所用(yong)(yong)(yong)(yong)(yong)到的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)一(yi)般都大(da)于(yu)1.5V，而(er)指針表(biao)的(de)(de)(de)R×1k以(yi)(yi)下(xia)的(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)檔是(shi)(shi)用(yong)(yong)(yong)(yong)(yong)表(biao)內(nei)的(de)(de)(de)1.5V電(dian)(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)(dian)的(de)(de)(de)，這(zhe)(zhe)樣，用(yong)(yong)(yong)(yong)(yong)R×1k以(yi)(yi)下(xia)的(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)檔測(ce)(ce)(ce)量穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)就(jiu)(jiu)如(ru)同測(ce)(ce)(ce)二極(ji)管(guan)一(yi)樣，具有完全的(de)(de)(de)單向導電(dian)(dian)(dian)(dian)性。但(dan)指針表(biao)的(de)(de)(de)R×10k檔是(shi)(shi)用(yong)(yong)(yong)(yong)(yong)9V或15V電(dian)(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)(dian)的(de)(de)(de)，在用(yong)(yong)(yong)(yong)(yong)R×10k測(ce)(ce)(ce)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)小于(yu)9V或15V的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)時，反向阻(zu)值(zhi)(zhi)(zhi)(zhi)(zhi)就(jiu)(jiu)不(bu)會是(shi)(shi)∞，而(er)是(shi)(shi)有一(yi)定阻(zu)值(zhi)(zhi)(zhi)(zhi)(zhi)，但(dan)這(zhe)(zhe)個(ge)(ge)(ge)阻(zu)值(zhi)(zhi)(zhi)(zhi)(zhi)還是(shi)(shi)要大(da)大(da)高(gao)于(yu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)正向阻(zu)值(zhi)(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)。如(ru)此，我(wo)(wo)們(men)就(jiu)(jiu)可以(yi)(yi)初步(bu)估測(ce)(ce)(ce)出(chu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)好壞(huai)。但(dan)是(shi)(shi)，好的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)還要有個(ge)(ge)(ge)準確的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)，業余(yu)條(tiao)件下(xia)怎么(me)估測(ce)(ce)(ce)出(chu)這(zhe)(zhe)個(ge)(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)呢？不(bu)難，再去找(zhao)一(yi)塊指針表(biao)來(lai)就(jiu)(jiu)可以(yi)(yi)了。方法(fa)是(shi)(shi)：先將一(yi)塊表(biao)置(zhi)于(yu)R×10k檔，其黑(hei)、紅(hong)表(biao)筆分別(bie)接在穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)陰(yin)極(ji)和陽極(ji)，這(zhe)(zhe)時就(jiu)(jiu)模(mo)擬出(chu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)實際工作狀態(tai)，再取另一(yi)塊表(biao)置(zhi)于(yu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)檔V×10V或V×50V（根(gen)據穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)）上(shang)(shang)，將紅(hong)、黑(hei)表(biao)筆分別(bie)搭接到剛(gang)才那(nei)塊表(biao)的(de)(de)(de)的(de)(de)(de)黑(hei)、紅(hong)表(biao)筆上(shang)(shang)，這(zhe)(zhe)時測(ce)(ce)(ce)出(chu)的(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)就(jiu)(jiu)基本上(shang)(shang)是(shi)(shi)這(zhe)(zhe)個(ge)(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)。說(shuo)“基本上(shang)(shang)”，是(shi)(shi)因為(wei)第一(yi)塊表(biao)對穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)偏(pian)置(zhi)電(dian)(dian)(dian)(dian)流相對正常(chang)使用(yong)(yong)(yong)(yong)(yong)時的(de)(de)(de)偏(pian)置(zhi)電(dian)(dian)(dian)(dian)流稍小些(xie)，所以(yi)(yi)測(ce)(ce)(ce)出(chu)的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)會稍偏(pian)大(da)一(yi)點，但(dan)基本相差不(bu)大(da)。這(zhe)(zhe)個(ge)(ge)(ge)方法(fa)只可估測(ce)(ce)(ce)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)小于(yu)指針表(biao)高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)。如(ru)果穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)管(guan)的(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)(zhi)太高(gao)，就(jiu)(jiu)只能用(yong)(yong)(yong)(yong)(yong)外加電(dian)(dian)(dian)(dian)源的(de)(de)(de)方法(fa)來(lai)測(ce)(ce)(ce)量了（這(zhe)(zhe)樣看來(lai)，我(wo)(wo)們(men)在選用(yong)(yong)(yong)(yong)(yong)指針表(biao)時，選用(yong)(yong)(yong)(yong)(yong)高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)(ya)為(wei)15V的(de)(de)(de)要比9V的(de)(de)(de)更適用(yong)(yong)(yong)(yong)(yong)些(xie)）。

6、測(ce)(ce)三極管(guan)(guan)(guan)(guan)：通(tong)常(chang)我們要用(yong)R×1kΩ檔，不(bu)管(guan)(guan)(guan)(guan)是(shi)(shi)(shi)(shi)NPN管(guan)(guan)(guan)(guan)還是(shi)(shi)(shi)(shi)PNP管(guan)(guan)(guan)(guan)，不(bu)管(guan)(guan)(guan)(guan)是(shi)(shi)(shi)(shi)小功(gong)率、中功(gong)率、大(da)(da)功(gong)率管(guan)(guan)(guan)(guan)，測(ce)(ce)其be結(jie)(jie)(jie)cb結(jie)(jie)(jie)都(dou)應(ying)(ying)呈現(xian)與二極管(guan)(guan)(guan)(guan)完(wan)全相同(tong)的(de)(de)單(dan)向導(dao)(dao)電(dian)(dian)(dian)性，反(fan)向電(dian)(dian)(dian)阻(zu)(zu)無窮(qiong)大(da)(da)，其正向電(dian)(dian)(dian)阻(zu)(zu)大(da)(da)約在(zai)(zai)10K左(zuo)右(you)。為進一(yi)步(bu)估測(ce)(ce)管(guan)(guan)(guan)(guan)子特性的(de)(de)好(hao)壞，必要時還應(ying)(ying)變換電(dian)(dian)(dian)阻(zu)(zu)檔位進行多(duo)次測(ce)(ce)量(liang)，方法(fa)是(shi)(shi)(shi)(shi)：置R×10Ω檔測(ce)(ce)PN結(jie)(jie)(jie)正向導(dao)(dao)通(tong)電(dian)(dian)(dian)阻(zu)(zu)都(dou)在(zai)(zai)大(da)(da)約200Ω左(zuo)右(you)；置R×1Ω檔測(ce)(ce)PN結(jie)(jie)(jie)正向導(dao)(dao)通(tong)電(dian)(dian)(dian)阻(zu)(zu)都(dou)在(zai)(zai)大(da)(da)約30Ω左(zuo)右(you)，（以(yi)上為47型(xing)表測(ce)(ce)得數據(ju)，其它型(xing)號表大(da)(da)概(gai)略有(you)(you)不(bu)同(tong)，可(ke)(ke)多(duo)試測(ce)(ce)幾(ji)個(ge)好(hao)管(guan)(guan)(guan)(guan)總結(jie)(jie)(jie)一(yi)下，做到心中有(you)(you)數）如果讀數偏(pian)大(da)(da)太多(duo)，可(ke)(ke)以(yi)斷定管(guan)(guan)(guan)(guan)子的(de)(de)特性不(bu)好(hao)。還可(ke)(ke)將表置于R×10kΩ再測(ce)(ce)，耐壓(ya)(ya)再低的(de)(de)管(guan)(guan)(guan)(guan)子（基本上三極管(guan)(guan)(guan)(guan)的(de)(de)耐壓(ya)(ya)都(dou)在(zai)(zai)30V以(yi)上），其cb結(jie)(jie)(jie)反(fan)向電(dian)(dian)(dian)阻(zu)(zu)也應(ying)(ying)在(zai)(zai)∞，但(dan)其be結(jie)(jie)(jie)的(de)(de)反(fan)向電(dian)(dian)(dian)阻(zu)(zu)可(ke)(ke)能會(hui)有(you)(you)些，表針(zhen)(zhen)(zhen)會(hui)稍有(you)(you)偏(pian)轉（一(yi)般不(bu)會(hui)超過(guo)滿量(liang)程的(de)(de)1/3，根據(ju)管(guan)(guan)(guan)(guan)子的(de)(de)耐壓(ya)(ya)不(bu)同(tong)而不(bu)同(tong)）。同(tong)樣(yang)，在(zai)(zai)用(yong)R×10kΩ檔測(ce)(ce)ec間(對NPN管(guan)(guan)(guan)(guan)）或ce間（對PNP管(guan)(guan)(guan)(guan)）的(de)(de)電(dian)(dian)(dian)阻(zu)(zu)時，表針(zhen)(zhen)(zhen)可(ke)(ke)能略有(you)(you)偏(pian)轉，但(dan)這不(bu)表示(shi)管(guan)(guan)(guan)(guan)子是(shi)(shi)(shi)(shi)壞的(de)(de)。但(dan)在(zai)(zai)用(yong)R×1kΩ以(yi)下檔測(ce)(ce)ce或ec間電(dian)(dian)(dian)阻(zu)(zu)時，表頭指示(shi)應(ying)(ying)為無窮(qiong)大(da)(da)，否則管(guan)(guan)(guan)(guan)子就是(shi)(shi)(shi)(shi)有(you)(you)問題(ti)。應(ying)(ying)該說(shuo)明(ming)一(yi)點的(de)(de)是(shi)(shi)(shi)(shi)，以(yi)上測(ce)(ce)量(liang)是(shi)(shi)(shi)(shi)針(zhen)(zhen)(zhen)對硅管(guan)(guan)(guan)(guan)而言(yan)的(de)(de)，對鍺管(guan)(guan)(guan)(guan)不(bu)適用(yong)。不(bu)過(guo)現(xian)在(zai)(zai)鍺管(guan)(guan)(guan)(guan)也很少見了。另外，所(suo)說(shuo)的(de)(de)“反(fan)向”是(shi)(shi)(shi)(shi)針(zhen)(zhen)(zhen)對PN結(jie)(jie)(jie)而言(yan)，對NPN管(guan)(guan)(guan)(guan)和(he)PNP管(guan)(guan)(guan)(guan)方向實(shi)際上是(shi)(shi)(shi)(shi)不(bu)同(tong)的(de)(de)。