摘 要運(yùn)用電磁理論和電路分析,闡述了串聯(lián)RLC電路的暫態(tài)過(guò)程與相關(guān)結(jié)論,提出了阻尼電磁振蕩次數(shù)的計(jì)算公式和振蕩儀的設(shè)計(jì)方案,解決了阻尼電磁振蕩儀與學(xué)生實(shí)驗(yàn)的設(shè)計(jì)、裝備與實(shí)驗(yàn)問(wèn)題。
關(guān)鍵詞:暫態(tài)過(guò)程;阻尼系數(shù);波阻抗;對(duì)數(shù)減縮率;振蕩次數(shù)
中圖分類(lèi)號(hào):O441 文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1671-489X(2007)04-0013-04
Research of Damping Electromagnetic Oscillation Experiment// Huang Gouming
Abstract This article utilizes the electromagnetic theory and the circuit analysis, elaborated connects the RLC electric circuit the transition process and the related conclusion, proposed the damping electromagnetic oscillation number of times formula and vibrates the meter the design proposal, has solved the design, the equipment and the experimental question which the damping electromagnetic oscillation meter and the student tests.
Key Words temporary process; damping coefficient; wave impedance; logqrithmic derement rate; vibration number of times
Author's address Department of Electronics and Communication Engineering, Changsha University, Changsha 410008
1 阻尼電磁振蕩儀的現(xiàn)狀及存在問(wèn)題
目前在高等院校(含高職)、中學(xué)(含職業(yè)技術(shù)中專(zhuān))的物理、電工、電路的教學(xué)中,關(guān)于阻尼電磁振蕩的演示實(shí)驗(yàn)和學(xué)生實(shí)驗(yàn),大多未能進(jìn)行,少數(shù)學(xué)校也是采用低頻振蕩電流并利用演示用靈敏電流計(jì)來(lái)進(jìn)行實(shí)驗(yàn)和觀察的。據(jù)筆者調(diào)查,大多工科大學(xué)畢業(yè)生都說(shuō)從來(lái)未親眼看到過(guò)如教材刊出的減幅電磁振蕩波形圖像。大學(xué)一般不做阻尼電磁振蕩的演示實(shí)驗(yàn),條件較好的中學(xué),也只是用J2434電磁振蕩演示儀配上大型演示電表J0402來(lái)看電表指針的減幅擺動(dòng),雖然看到了減幅振蕩電流現(xiàn)象,但仍未真正觀察到減幅振蕩波形圖像。況且實(shí)驗(yàn)時(shí),由于振蕩的起始電流較大(約3~6mA),大型演示電表的阻尼大,往往只看到電表指針彈擊止動(dòng)柱(或超過(guò)電表最大刻度)后,擺動(dòng)幾次就停止了。這與用干電池加接一個(gè)電阻后直接碰觸一下電表兩接線(xiàn)柱所產(chǎn)生的效果相差不大,實(shí)驗(yàn)者(更何況于學(xué)生)很難分辨和說(shuō)明前者是減幅振蕩而后者不是,有的教師只好要學(xué)生觀察幾次兩種實(shí)驗(yàn)中電表指針從擺動(dòng)到停止的區(qū)別而強(qiáng)求學(xué)生信服,若改接于示波器,在其光屏上更無(wú)法觀察到減幅振蕩圖像。……