【萬(wan)能表】萬(wan)能表的(de)使用(yong)方法 電工用的(de)萬能表的(de)使用方法

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(zu)檔，指針表的表筆輸出電(dian)流相對數字表來說要(yao)大很(hen)多(duo)，用R×1Ω檔可以使揚(yang)聲器發(fa)出響(xiang)亮的“噠”聲，用R×10kΩ檔甚至(zhi)可以點(dian)亮發(fa)光二極管（LED）。

3、在(zai)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)檔，指(zhi)針表內阻(zu)相(xiang)對數字表來說比較(jiao)小(xiao)，測(ce)(ce)(ce)量(liang)精度相(xiang)比較(jiao)差。某些高(gao)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)微電(dian)(dian)(dian)(dian)流的場合甚至無(wu)法測(ce)(ce)(ce)準，因為其(qi)內阻(zu)會對被(bei)測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)路造成(cheng)影響（比如在(zai)測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)視(shi)機顯(xian)像管的加(jia)速級(ji)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)時(shi)測(ce)(ce)(ce)量(liang)值會比實際值低很多）。數字表電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)檔的內阻(zu)很大，至少在(zai)兆歐級(ji)，對被(bei)測(ce)(ce)(ce)電(dian)(dian)(dian)(dian)路影響很小(xiao)。但極高(gao)的輸出(chu)(chu)阻(zu)抗使其(qi)易受感應電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的影響，在(zai)一些電(dian)(dian)(dian)(dian)磁(ci)干(gan)擾(rao)比較(jiao)強的場合測(ce)(ce)(ce)出(chu)(chu)的數據可能是虛(xu)的。

4、總(zong)之，在相對來說大電流高電壓(ya)的(de)模擬電路測量中適(shi)(shi)用(yong)指(zhi)針表，比(bi)如電視機、音響功放(fang)。在低電壓(ya)小電流的(de)數字(zi)電路測量中適(shi)(shi)用(yong)數字(zi)表，比(bi)如BP機、手(shou)機等(deng)。不(bu)是(shi)絕對的(de)，可根據情況選用(yong)指(zhi)針表和數字(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、動圈式話筒：用(yong)R×1Ω檔，任(ren)一(yi)表筆(bi)接一(yi)端(duan)，另一(yi)表筆(bi)點觸另一(yi)端(duan)，正常時會發(fa)出(chu)清脆響(xiang)量的“噠”聲(sheng)。如果(guo)不(bu)響(xiang)，則(ze)是(shi)線圈斷了，如果(guo)響(xiang)聲(sheng)小(xiao)而尖，則(ze)是(shi)有擦(ca)圈問題，也不(bu)能(neng)用(yong)。

2、測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)：用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻檔(dang)，根據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)選擇適當的(de)(de)量(liang)(liang)(liang)程，并注意(yi)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)時對(dui)(dui)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)黑(hei)表(biao)筆要(yao)(yao)接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)正(zheng)極。①、估(gu)測(ce)(ce)(ce)(ce)微(wei)(wei)波法級電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)的(de)(de)大(da)小(xiao)(xiao)：可(ke)憑經驗(yan)或(huo)參(can)(can)照(zhao)相同(tong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)的(de)(de)標(biao)準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，根據指(zhi)針(zhen)(zhen)(zhen)擺(bai)動(dong)的(de)(de)最大(da)幅度來判定(ding)(ding)(ding)。所(suo)參(can)(can)照(zhao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)不(bu)必耐壓值也(ye)一(yi)(yi)樣(yang)，只(zhi)要(yao)(yao)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)相同(tong)即(ji)(ji)可(ke)，例如(ru)估(gu)測(ce)(ce)(ce)(ce)一(yi)(yi)個100μF/250V的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)可(ke)用一(yi)(yi)個100μF/25V的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)來參(can)(can)照(zhao)，只(zhi)要(yao)(yao)它(ta)們指(zhi)針(zhen)(zhen)(zhen)擺(bai)動(dong)最大(da)幅度一(yi)(yi)樣(yang)，即(ji)(ji)可(ke)斷定(ding)(ding)(ding)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)一(yi)(yi)樣(yang)。②、估(gu)測(ce)(ce)(ce)(ce)皮法級電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)大(da)小(xiao)(xiao)：要(yao)(yao)用R×10kΩ檔(dang)，但只(zhi)能測(ce)(ce)(ce)(ce)到1000pF以(yi)上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)。對(dui)(dui)1000pF或(huo)稍大(da)一(yi)(yi)點的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，只(zhi)要(yao)(yao)表(biao)針(zhen)(zhen)(zhen)稍有(you)(you)擺(bai)動(dong)，即(ji)(ji)可(ke)認為容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)夠了(le)。③、測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)是否漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)：對(dui)(dui)一(yi)(yi)千微(wei)(wei)法以(yi)上的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)，可(ke)先用R×10Ω檔(dang)將其(qi)快速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并初步估(gu)測(ce)(ce)(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)(liang)，然后改到R×1kΩ檔(dang)繼(ji)續測(ce)(ce)(ce)(ce)一(yi)(yi)會兒(er)，這(zhe)時指(zhi)針(zhen)(zhen)(zhen)不(bu)應回(hui)(hui)返(fan)，而應停(ting)(ting)在(zai)或(huo)十(shi)分接近(jin)∞處(chu)，否則就是有(you)(you)漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)現象。對(dui)(dui)一(yi)(yi)些幾(ji)十(shi)微(wei)(wei)法以(yi)下的(de)(de)定(ding)(ding)(ding)時或(huo)振(zhen)(zhen)蕩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)（比如(ru)彩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)振(zhen)(zhen)蕩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)），對(dui)(dui)其(qi)漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)特性要(yao)(yao)求非(fei)常高，只(zhi)要(yao)(yao)稍有(you)(you)漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)就不(bu)能用，這(zhe)時可(ke)在(zai)R×1kΩ檔(dang)充(chong)(chong)完電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)后再改用R×10kΩ檔(dang)繼(ji)續測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)，同(tong)樣(yang)表(biao)針(zhen)(zhen)(zhen)應停(ting)(ting)在(zai)∞處(chu)而不(bu)應回(hui)(hui)返(fan)。

3、在(zai)路(lu)測(ce)(ce)二(er)極(ji)管(guan)、三(san)極(ji)管(guan)、穩壓(ya)管(guan)好壞(huai)：因(yin)為(wei)在(zai)實際(ji)電(dian)(dian)(dian)路(lu)中，三(san)極(ji)管(guan)的(de)(de)偏置電(dian)(dian)(dian)阻(zu)(zu)或(huo)二(er)極(ji)管(guan)、穩壓(ya)管(guan)的(de)(de)周邊(bian)電(dian)(dian)(dian)阻(zu)(zu)一(yi)般(ban)都(dou)(dou)比較(jiao)大(da)(da)(da)，大(da)(da)(da)都(dou)(dou)在(zai)幾(ji)百幾(ji)千(qian)歐(ou)姆以(yi)(yi)上，這(zhe)樣，我(wo)們就可(ke)以(yi)(yi)用萬用表(biao)的(de)(de)R×10Ω或(huo)R×1Ω檔(dang)(dang)(dang)來(lai)在(zai)路(lu)測(ce)(ce)量PN結的(de)(de)好壞(huai)。在(zai)路(lu)測(ce)(ce)量時(shi)，用R×10Ω檔(dang)(dang)(dang)測(ce)(ce)PN結應(ying)有(you)較(jiao)明顯(xian)的(de)(de)正(zheng)反(fan)(fan)向(xiang)(xiang)特性(xing)(xing)（如(ru)(ru)果(guo)(guo)正(zheng)反(fan)(fan)向(xiang)(xiang)電(dian)(dian)(dian)阻(zu)(zu)相差不(bu)太(tai)(tai)明顯(xian)，可(ke)改用R×1Ω檔(dang)(dang)(dang)來(lai)測(ce)(ce)），一(yi)般(ban)正(zheng)向(xiang)(xiang)電(dian)(dian)(dian)阻(zu)(zu)在(zai)R×10Ω檔(dang)(dang)(dang)測(ce)(ce)時(shi)表(biao)針(zhen)應(ying)指(zhi)示在(zai)200Ω左右，在(zai)R×1Ω檔(dang)(dang)(dang)測(ce)(ce)時(shi)表(biao)針(zhen)應(ying)指(zhi)示在(zai)30Ω左右（根據不(bu)同表(biao)型可(ke)能略有(you)出(chu)入）。如(ru)(ru)果(guo)(guo)測(ce)(ce)量結果(guo)(guo)正(zheng)向(xiang)(xiang)阻(zu)(zu)值太(tai)(tai)大(da)(da)(da)或(huo)反(fan)(fan)向(xiang)(xiang)阻(zu)(zu)值太(tai)(tai)小，都(dou)(dou)說明這(zhe)個PN結有(you)問(wen)題(ti)，這(zhe)個管(guan)子(zi)也就有(you)問(wen)題(ti)了(le)。這(zhe)種(zhong)方法(fa)對(dui)于(yu)維修時(shi)特別(bie)有(you)效，可(ke)以(yi)(yi)非(fei)常(chang)快速地找出(chu)壞(huai)管(guan)，甚至可(ke)以(yi)(yi)測(ce)(ce)出(chu)尚(shang)未完(wan)全(quan)壞(huai)掉但特性(xing)(xing)變壞(huai)的(de)(de)管(guan)子(zi)。比如(ru)(ru)當你用小阻(zu)(zu)值檔(dang)(dang)(dang)測(ce)(ce)量某個PN結正(zheng)向(xiang)(xiang)電(dian)(dian)(dian)阻(zu)(zu)過大(da)(da)(da)，如(ru)(ru)果(guo)(guo)你把它焊下來(lai)用常(chang)用的(de)(de)R×1kΩ檔(dang)(dang)(dang)再測(ce)(ce)，可(ke)能還是正(zheng)常(chang)的(de)(de)，其實這(zhe)個管(guan)子(zi)的(de)(de)特性(xing)(xing)已經變壞(huai)了(le)，不(bu)能正(zheng)常(chang)工作或(huo)不(bu)穩定了(le)。

4、測(ce)電阻(zu)：重要的是(shi)要選(xuan)好量(liang)程(cheng)，當指(zhi)針指(zhi)示(shi)于(yu)1/3～2/3滿量(liang)程(cheng)時測(ce)量(liang)精度最(zui)高(gao)，讀數(shu)最(zui)準確。要注意的是(shi)，在(zai)用R×10k電阻(zu)檔測(ce)兆歐級的大阻(zu)值電阻(zu)時，不可將手指(zhi)捏在(zai)電阻(zu)兩端，這樣人體電阻(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)二極管(guan)(guan)：我(wo)們通常(chang)所用(yong)(yong)(yong)(yong)到的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)一(yi)(yi)(yi)(yi)般都大(da)于(yu)1.5V，而(er)指針(zhen)表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)R×1k以下的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)檔是(shi)(shi)用(yong)(yong)(yong)(yong)表(biao)(biao)(biao)(biao)內(nei)的(de)(de)(de)(de)(de)1.5V電(dian)(dian)(dian)(dian)(dian)池供(gong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)，這(zhe)(zhe)(zhe)(zhe)樣(yang)，用(yong)(yong)(yong)(yong)R×1k以下的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)檔測(ce)(ce)(ce)量穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)就(jiu)(jiu)如同測(ce)(ce)(ce)二極管(guan)(guan)一(yi)(yi)(yi)(yi)樣(yang)，具(ju)有完全的(de)(de)(de)(de)(de)單(dan)向導電(dian)(dian)(dian)(dian)(dian)性。但指針(zhen)表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)R×10k檔是(shi)(shi)用(yong)(yong)(yong)(yong)9V或(huo)15V電(dian)(dian)(dian)(dian)(dian)池供(gong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)，在用(yong)(yong)(yong)(yong)R×10k測(ce)(ce)(ce)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)小(xiao)于(yu)9V或(huo)15V的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)時(shi)(shi)，反向阻(zu)(zu)值(zhi)(zhi)(zhi)(zhi)就(jiu)(jiu)不(bu)會是(shi)(shi)∞，而(er)是(shi)(shi)有一(yi)(yi)(yi)(yi)定阻(zu)(zu)值(zhi)(zhi)(zhi)(zhi)，但這(zhe)(zhe)(zhe)(zhe)個(ge)(ge)阻(zu)(zu)值(zhi)(zhi)(zhi)(zhi)還(huan)是(shi)(shi)要(yao)大(da)大(da)高于(yu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)正向阻(zu)(zu)值(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)(de)(de)。如此，我(wo)們就(jiu)(jiu)可以初(chu)步估(gu)測(ce)(ce)(ce)出(chu)(chu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)好壞。但是(shi)(shi)，好的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)還(huan)要(yao)有個(ge)(ge)準確的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)，業余(yu)條件下怎么估(gu)測(ce)(ce)(ce)出(chu)(chu)這(zhe)(zhe)(zhe)(zhe)個(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)呢？不(bu)難，再去(qu)找一(yi)(yi)(yi)(yi)塊(kuai)指針(zhen)表(biao)(biao)(biao)(biao)來就(jiu)(jiu)可以了(le)。方法(fa)(fa)是(shi)(shi)：先將(jiang)一(yi)(yi)(yi)(yi)塊(kuai)表(biao)(biao)(biao)(biao)置于(yu)R×10k檔，其黑(hei)、紅(hong)表(biao)(biao)(biao)(biao)筆(bi)(bi)分(fen)別接在穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)陰極和陽極，這(zhe)(zhe)(zhe)(zhe)時(shi)(shi)就(jiu)(jiu)模擬(ni)出(chu)(chu)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)實際工作狀(zhuang)態，再取另一(yi)(yi)(yi)(yi)塊(kuai)表(biao)(biao)(biao)(biao)置于(yu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)檔V×10V或(huo)V×50V（根據穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)）上(shang)(shang)，將(jiang)紅(hong)、黑(hei)表(biao)(biao)(biao)(biao)筆(bi)(bi)分(fen)別搭接到剛才那塊(kuai)表(biao)(biao)(biao)(biao)的(de)(de)(de)(de)(de)的(de)(de)(de)(de)(de)黑(hei)、紅(hong)表(biao)(biao)(biao)(biao)筆(bi)(bi)上(shang)(shang)，這(zhe)(zhe)(zhe)(zhe)時(shi)(shi)測(ce)(ce)(ce)出(chu)(chu)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)就(jiu)(jiu)基本(ben)(ben)上(shang)(shang)是(shi)(shi)這(zhe)(zhe)(zhe)(zhe)個(ge)(ge)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)。說“基本(ben)(ben)上(shang)(shang)”，是(shi)(shi)因為第(di)一(yi)(yi)(yi)(yi)塊(kuai)表(biao)(biao)(biao)(biao)對穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)偏置電(dian)(dian)(dian)(dian)(dian)流(liu)相對正常(chang)使用(yong)(yong)(yong)(yong)時(shi)(shi)的(de)(de)(de)(de)(de)偏置電(dian)(dian)(dian)(dian)(dian)流(liu)稍小(xiao)些(xie)，所以測(ce)(ce)(ce)出(chu)(chu)的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)會稍偏大(da)一(yi)(yi)(yi)(yi)點，但基本(ben)(ben)相差不(bu)大(da)。這(zhe)(zhe)(zhe)(zhe)個(ge)(ge)方法(fa)(fa)只可估(gu)測(ce)(ce)(ce)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)小(xiao)于(yu)指針(zhen)表(biao)(biao)(biao)(biao)高壓(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)。如果穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)管(guan)(guan)的(de)(de)(de)(de)(de)穩(wen)(wen)(wen)壓(ya)(ya)(ya)(ya)值(zhi)(zhi)(zhi)(zhi)太高，就(jiu)(jiu)只能(neng)用(yong)(yong)(yong)(yong)外加電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)(de)(de)(de)(de)方法(fa)(fa)來測(ce)(ce)(ce)量了(le)（這(zhe)(zhe)(zhe)(zhe)樣(yang)看來，我(wo)們在選(xuan)用(yong)(yong)(yong)(yong)指針(zhen)表(biao)(biao)(biao)(biao)時(shi)(shi)，選(xuan)用(yong)(yong)(yong)(yong)高壓(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)為15V的(de)(de)(de)(de)(de)要(yao)比9V的(de)(de)(de)(de)(de)更適用(yong)(yong)(yong)(yong)些(xie)）。

6、測(ce)(ce)三極(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)：通(tong)(tong)常(chang)我們要用R×1kΩ檔(dang)(dang)，不管(guan)(guan)(guan)(guan)(guan)(guan)(guan)是(shi)(shi)NPN管(guan)(guan)(guan)(guan)(guan)(guan)(guan)還是(shi)(shi)PNP管(guan)(guan)(guan)(guan)(guan)(guan)(guan)，不管(guan)(guan)(guan)(guan)(guan)(guan)(guan)是(shi)(shi)小功(gong)率、中功(gong)率、大(da)(da)功(gong)率管(guan)(guan)(guan)(guan)(guan)(guan)(guan)，測(ce)(ce)其(qi)(qi)be結(jie)cb結(jie)都(dou)應(ying)呈現與(yu)二(er)極(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)完(wan)全相同(tong)(tong)(tong)的(de)(de)(de)(de)單(dan)向(xiang)導電(dian)(dian)性(xing)，反向(xiang)電(dian)(dian)阻無窮大(da)(da)，其(qi)(qi)正向(xiang)電(dian)(dian)阻大(da)(da)約(yue)(yue)在(zai)(zai)10K左(zuo)右。為進一(yi)步估(gu)測(ce)(ce)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)特性(xing)的(de)(de)(de)(de)好(hao)壞(huai)(huai)，必要時還應(ying)變換電(dian)(dian)阻檔(dang)(dang)位進行多(duo)次測(ce)(ce)量，方(fang)法是(shi)(shi)：置R×10Ω檔(dang)(dang)測(ce)(ce)PN結(jie)正向(xiang)導通(tong)(tong)電(dian)(dian)阻都(dou)在(zai)(zai)大(da)(da)約(yue)(yue)200Ω左(zuo)右；置R×1Ω檔(dang)(dang)測(ce)(ce)PN結(jie)正向(xiang)導通(tong)(tong)電(dian)(dian)阻都(dou)在(zai)(zai)大(da)(da)約(yue)(yue)30Ω左(zuo)右，（以(yi)上(shang)為47型表(biao)(biao)(biao)測(ce)(ce)得數據，其(qi)(qi)它型號表(biao)(biao)(biao)大(da)(da)概略(lve)有(you)不同(tong)(tong)(tong)，可(ke)多(duo)試測(ce)(ce)幾個好(hao)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)總結(jie)一(yi)下(xia)，做到心中有(you)數）如果讀數偏大(da)(da)太多(duo)，可(ke)以(yi)斷定管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)(de)(de)(de)特性(xing)不好(hao)。還可(ke)將表(biao)(biao)(biao)置于R×10kΩ再測(ce)(ce)，耐(nai)壓(ya)(ya)再低的(de)(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)（基本上(shang)三極(ji)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)耐(nai)壓(ya)(ya)都(dou)在(zai)(zai)30V以(yi)上(shang)），其(qi)(qi)cb結(jie)反向(xiang)電(dian)(dian)阻也應(ying)在(zai)(zai)∞，但其(qi)(qi)be結(jie)的(de)(de)(de)(de)反向(xiang)電(dian)(dian)阻可(ke)能會有(you)些，表(biao)(biao)(biao)針(zhen)會稍有(you)偏轉（一(yi)般不會超過滿量程的(de)(de)(de)(de)1/3，根(gen)據管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)(de)(de)(de)耐(nai)壓(ya)(ya)不同(tong)(tong)(tong)而不同(tong)(tong)(tong)）。同(tong)(tong)(tong)樣，在(zai)(zai)用R×10kΩ檔(dang)(dang)測(ce)(ce)ec間(對NPN管(guan)(guan)(guan)(guan)(guan)(guan)(guan)）或ce間（對PNP管(guan)(guan)(guan)(guan)(guan)(guan)(guan)）的(de)(de)(de)(de)電(dian)(dian)阻時，表(biao)(biao)(biao)針(zhen)可(ke)能略(lve)有(you)偏轉，但這不表(biao)(biao)(biao)示管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)是(shi)(shi)壞(huai)(huai)的(de)(de)(de)(de)。但在(zai)(zai)用R×1kΩ以(yi)下(xia)檔(dang)(dang)測(ce)(ce)ce或ec間電(dian)(dian)阻時，表(biao)(biao)(biao)頭指示應(ying)為無窮大(da)(da)，否(fou)則(ze)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)就(jiu)是(shi)(shi)有(you)問題。應(ying)該說(shuo)(shuo)明一(yi)點的(de)(de)(de)(de)是(shi)(shi)，以(yi)上(shang)測(ce)(ce)量是(shi)(shi)針(zhen)對硅管(guan)(guan)(guan)(guan)(guan)(guan)(guan)而言的(de)(de)(de)(de)，對鍺(zang)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)不適用。不過現在(zai)(zai)鍺(zang)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)也很少見了。另外，所說(shuo)(shuo)的(de)(de)(de)(de)“反向(xiang)”是(shi)(shi)針(zhen)對PN結(jie)而言，對NPN管(guan)(guan)(guan)(guan)(guan)(guan)(guan)和PNP管(guan)(guan)(guan)(guan)(guan)(guan)(guan)方(fang)向(xiang)實際上(shang)是(shi)(shi)不同(tong)(tong)(tong)的(de)(de)(de)(de)。