數字萬用表由於具有測量精確、取值方便、功能齊全等優點,因此深受無線電愛好者的歡迎、最普通的數字方用表一般具有電阻測量、通斷聲響檢測、二極管正向導通電壓測量。交流直流電壓電流測量、三極管放大倍數及性能測量等。有些數字萬用表則增加了電容容量測量、頻率測量、溫度測量、數shu據ju記ji憶yi及ji語yu音yin報bao數shu等deng功gong能neng,給gei實shi際ji檢jian測ce工gong作zuo帶dai來lai很hen大da的de方fang便bian。但dan是shi,數shu字zi方fang用yong表biao由you於yu使shi用yong不bu當dang,在zai實shi際ji檢jian測ce時shi易yi造zao成cheng表biao內nei元yuan件jian損sun壞huai,產chan生sheng故gu障zhang。本ben人ren根gen據ju造zao成cheng數shu字zi萬wan用yong表biao損sun壞huai的de實shi際ji情qing況kuang,總zong結jie出chu數shu字zi方fang用yong表biao在zai使shi用yong中zhong的de注zhu意yi事shi項xiang,供gong初chu學xue初chu用yong者zhe參can考kao,以yi盡jin量liang防fang止zhi數shu字zi萬wan用yong表biao的de損sun壞huai。
shuziwanyongbiaosunhuaizaidaduoshuqingkuangxiashiyinceliangdangweicuowuzaocheng,ruzaiceliangjiaoliushidianshi,celiangdangweixuanzezhiyudianzudang,zhezhongqingkuangxiabiaobiyidanjiechushidian,shunjianjikezaochengwanyongbiaoneibuyuanjiansunhuai。yinci,zaishiyongwanyongbiaoceliangqianyidingyaoxianjianzhaceliangdangweishifouzhengque。zaishiyongwanbi,jiangceliangxuanzezhiyujiaoliu750V或者直流1000V處,這樣在下次測量時無論誤測什麼參數,都不會引起數字萬用表損壞.
有些數字萬用表損壞是由於測量的電壓電流超過量程範圍所造成的.如在交流20Vdangweiceliangshidian,henyiyinqishuziwanyongbiaojiaoliufangdadianlusunhuai,shiwanyongbiaoshiqujiaoliucelianggongneng。zaiceliangzhiliudianyashi,suocedianyachaochuceliangliangcheng,tongyangyizaochengbiaoneidianluguzhang。zaiceliangdianliushiruguoshijidianliuzhichaoguoliangcheng,yibanjinyinqiwanyongbiaoneidebaoxiansishaoduan,buhuizaochengqitasunhuai。suoyizaiceliangdianyacanshushi,ruguobuzhidaosuocedianyadedazhifanwei,yingxianbaceliangdangzhiyuzuigaodang,tongguoceliangqizhihouzaihuandangceliang,yidedaobijiaojingquedeshuzhi。ruguosuoyaoceliangdedianyashuzhiyuanchaochuwanyongbiaosuonengceliangdezuidaliangcheng,yinglingpeigaozuceliangbiaobi。rujianceheibaicaidiandedieryangjigaoyajijujiaogaoya。
多數數字萬用表的直流電壓上限量程為1000V,因此測量直流電壓時,最高電壓值在1000V以下,一般不會損壞萬用表。如果超出1000V,則(ze)很(hen)有(you)可(ke)能(neng)造(zao)成(cheng)萬(wan)用(yong)表(biao)損(sun)壞(huai)。但(dan)是(shi),不(bu)同(tong)的(de)數(shu)字(zi)萬(wan)用(yong)表(biao)的(de)可(ke)測(ce)量(liang)電(dian)壓(ya)上(shang)限(xian)值(zhi)可(ke)能(neng)有(you)所(suo)不(bu)同(tong)。如(ru)果(guo)測(ce)量(liang)的(de)電(dian)壓(ya)超(chao)出(chu)量(liang)程(cheng),可(ke)采(cai)取(qu)電(dian)阻(zu)降(jiang)壓(ya)的(de)方(fang)法(fa)加(jia)以(yi)測(ce)量(liang)。另(ling)外(wai),在(zai)測(ce)量(liang)40O~1000V的(de)直(zhi)流(liu)高(gao)電(dian)壓(ya)時(shi),表(biao)筆(bi)與(yu)測(ce)量(liang)處(chu)一(yi)定(ding)要(yao)接(jie)觸(chu)好(hao),不(bu)能(neng)有(you)任(ren)何(he)抖(dou)動(dong),否(fou)則(ze),除(chu)了(le)可(ke)能(neng)會(hui)造(zao)成(cheng)萬(wan)用(yong)表(biao)損(sun)壞(huai)而(er)使(shi)測(ce)量(liang)不(bu)準(zhun)確(que)外(wai),嚴(yan)重(zhong)時(shi)還(hai)可(ke)使(shi)萬(wan)用(yong)表(biao)無(wu)任(ren)何(he)顯(xian)示(shi).
在測量電阻時,應注意一定不要帶電測量。
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