中心議題：

• 所有類型的探頭共有的特性簡介

數字示波器是shi電dian子zi工gong程cheng師shi使shi用yong最zui廣guang泛fan的de一yi種zhong測ce試shi測ce量liang儀yi器qi，從cong測ce試shi係xi統tong的de角jiao度du來lai看kan
，數shu字zi示shi波bo器qi係xi統tong包bao括kuo主zhu機ji和he探tan頭tou兩liang主zhu要yao組zu成cheng部bu分fen，示shi波bo器qi探tan頭tou與yu主zhu機ji的de關guan係xi就jiu好hao比bi汽qi車che與yu輪lun子zi，汽qi車che車che身shen通tong過guo輪lun子zi才cai能neng接jie觸chu到dao地di麵mian
，才cai能neng發fa揮hui行xing駛shi的de功gong能neng，示shi波bo器qi主zhu機ji也ye是shi通tong過guo探tan頭tou才cai能neng接jie觸chu到dao信xin號hao，才cai能neng執zhi行xing信xin號hao采cai集ji與yu測ce試shi的de功gong能neng。缺que少shao輪lun子zi的de汽qi車che就jiu是shi一yi堆dui廢fei鐵tie，沒mei有you探tan頭tou的de示shi波bo器qi也ye隻zhi能neng是shi個ge擺bai設she。示shi波bo器qi探tan頭tou不bu僅jin僅jin是shi把ba測ce試shi信xin號hao送song進jin示shi波bo器qi輸shu入ru端duan的de一yi根gen導dao線xian
，而er且qie是shi儀yi器qi係xi統tong的de重zhong要yao組zu成cheng部bu分fen。根gen據ju特te性xing和he應ying用yong場chang合he的de不bu同tong，探tan頭tou可ke以yi分fen成cheng很hen多duo類lei型xing號hao
，以yi適shi應ying各ge種zhong不bu同tong信xin號hao測ce試shi的de需xu要yao。其qi中zhong一yi類lei稱cheng為wei有you源yuan探tan頭tou，其qi內nei部bu包bao含han有you源yuan電dian子zi元yuan件jian（主要是晶體管）可ke以yi提ti供gong信xin號hao放fang大da能neng力li
，不bu含han有you源yuan器qi件jian的de探tan頭tou稱cheng為wei無wu源yuan探tan頭tou
，其qi中zhong隻zhi包bao含han無wu源yuan器qi件jian如ru電dian阻zu電dian容rong等deng。這zhe類lei探tan頭tou通tong常chang隻zhi能neng對dui信xin號hao進jin行xing衰shuai減jian。我wo們men可ke以yi繼ji續xu將jiang有you源yuan和he無wu源yuan探tan頭tou分fen成cheng更geng專zhuan門men的de類lei別bie型xing號hao，每mei種zhong探tan頭tou的de工gong作zuo原yuan理li

、應用場合和使用注意事項都不一樣。

本節闡述所有類型探頭共有的一些特性。

一

、探頭屏蔽
gongchengshifuyushiboqitantoudeyigezhongyaoshimingjiushiquebaozhiyouxiwangguancedexinhaocainengtongguotaxianshizaishiboqipingmushang。ruguowomenjinjinshiyongyigendaoxianlaidaititantou，natadezuoyongjiuhaoxiangshiyigentianxian，keyicongwuxianguangbo，yidongdianhua、電機、50或60Hz的(de)電(dian)源(yuan)的(de)交(jiao)流(liu)聲(sheng)甚(shen)至(zhi)當(dang)地(di)業(ye)餘(yu)無(wu)線(xian)電(dian)愛(ai)好(hao)者(zhe)那(na)裏(li)接(jie)收(shou)到(dao)很(hen)多(duo)不(bu)希(xi)望(wang)的(de)幹(gan)擾(rao)信(xin)號(hao)。這(zhe)些(xie)噪(zao)聲(sheng)甚(shen)至(zhi)還(hai)能(neng)反(fan)向(xiang)注(zhu)入(ru)到(dao)被(bei)測(ce)電(dian)路(lu)中(zhong)使(shi)信(xin)號(hao)發(fa)生(sheng)畸(ji)變(bian)，所(suo)以(yi)我(wo)們(men)首(shou)先(xian)需(xu)要(yao)的(de)是(shi)能(neng)夠(gou)提(ti)供(gong)屏(ping)蔽(bi)功(gong)能(neng)的(de)電(dian)纜(lan)。良(liang)好(hao)設(she)計(ji)的(de)示(shi)波(bo)器(qi)探(tan)頭(tou)的(de)屏(ping)蔽(bi)電(dian)纜(lan)通(tong)過(guo)探(tan)頭(tou)尖(jian)端(duan)的(de)接(jie)地(di)線(xian)和(he)被(bei)測(ce)電(dian)路(lu)連(lian)接(jie)
，從(cong)而(er)保(bao)證(zheng)了(le)很(hen)好(hao)的(de)噪(zao)聲(sheng)抑(yi)製(zhi)性(xing)能(neng)。

二、探頭帶寬
大家都了解示波器通道帶寬的定義，輸入正弦波信號幅度被降低到-3dB(0.707倍)shiduiyingdepinlvjiduiyingshiboqimonidaikuanzhegezhibiao，juedingzhegezhibiaodeshiqianduanfangdaqijiandexingneng。tongyangtantouyejuyouyouxiandemonidaikuan。ruguobashiboqizuoweiyigexitonglaikaocha
，qizongtidaikuanyouzhujidaikuanhetantoudaikuangongtongjueding
，gengzhuanyedeshuxuegongshibiaominglezhezhongguanlianxing：