本文選題：電流 + 并聯(lián)��； 參考：《河北大學》2017年碩士論文

【摘要】：隨著社會的智能化和科學技術(shù)日新月異發(fā)展的年代,在日常的生活和學習中越來越多接觸到新的電子產(chǎn)品,PCB電路板構(gòu)成的產(chǎn)品在常規(guī)檢測與維修工作上成了產(chǎn)品檢驗的有力的保障。批量檢測電路板的好壞和電路電流的檢測技術(shù)亟待進一步簡便、快捷、精準的測量。通常電流測量時需要將測量儀表串聯(lián)接入電路,或者將被測導線穿過測量磁環(huán)。因此,研究一種可以與導線并聯(lián)測量電流的方法,在PCB等電流測量檢測等場合可帶來便利,具有實用意義。本研究通過分析常見幾種電流測量方法,深入分析其適用場合和測量利弊,針對目前PCB電路板在線測量的市場現(xiàn)象,設(shè)計了一種低成本、可以與微小阻值導線并聯(lián)測量導線中電流的方法和電路。本測試電路依托運算放大器的特性和工作方式,選用具備高增益、低失調(diào)的高精度型運算放大器為核心器件,設(shè)計實現(xiàn)了并聯(lián)式電流測量方法。此種方法改變了在傳統(tǒng)測量PCB板電流的檢測方法會在某些特定的場合給測試的帶來不便,使其在PCB電路板測試檢修等較小電流情況實現(xiàn)不需要斷開PCB銅箔線條即可測量電流。本文設(shè)計給出了一種并聯(lián)式電流測量電路,包括基于OP177型精密運放的主測量電路,以及由取樣電阻和IRF630型VMOS管等構(gòu)成的測量電流量程擴展電路。論文對電路原理進行了詳細分析和仿真。對元器件的遴選進行了分析對比。采用PROTEUS對設(shè)計的電路進行了仿真驗證。仿真結(jié)果表明,當被測導線阻值在≥50mΩ時,2mA~200mA范圍內(nèi)電流測量誤差≤4%,在3mA~200mA范圍內(nèi)電流測量誤差㩳3%。實際搭建電路中當被測導線阻值在≥50mΩ時,2mA~200mA范圍內(nèi)電流測量誤差≤6%,在4mA~200m A范圍內(nèi)電流測量誤差㩳2%。測試表明,該電路可以實現(xiàn)并聯(lián)電流的測量,測量誤差及變化趨勢和仿真結(jié)果基本相符。主要是由于仿真的環(huán)境為理想的環(huán)境下測量而實際測量電路的時候受實驗設(shè)備、環(huán)境、人為讀數(shù)等諸多因素的影響。
[Abstract]:With the society's intelligence and the rapid development of science and technology, In the daily life and study, more and more products made up of new electronic products, PCB circuit board, have become the powerful guarantee of product inspection in the routine inspection and maintenance work. The quality of the circuit board and the current detection technology need to be further simple, fast and accurate measurement. Current measurement usually involves connecting the instrument in series to the circuit or traversing the measuring ring. Therefore, it is of practical significance to study a method for measuring current in parallel with conductors, which can be used in PCB and other situations. Through analyzing several common current measurement methods, the paper deeply analyzes the applicable situation, advantages and disadvantages of the measurement, and designs a low cost for the current market phenomenon of online measurement of PCB circuit board. A method and circuit for measuring the current in a wire in parallel with a small resistance conductor. Based on the characteristics and working mode of the operational amplifier, this test circuit chooses the high gain and low offset high precision operational amplifier as the core device, and designs and implements the parallel current measurement method. This method changes the traditional method of measuring the current of PCB board, which will bring inconvenience to the test in some special occasions, and make it realize that the current can be measured without disconnecting the copper foil line of PCB in smaller current condition such as PCB circuit board test and repair. In this paper, a parallel current measuring circuit is designed, including the main measuring circuit based on OP177 precise operational amplifier, and the measuring current range expanding circuit composed of sampling resistor and IRF630 type VMOS transistor. The circuit principle is analyzed and simulated in detail. The selection of components is analyzed and compared. The designed circuit is verified by PROTEUS. The simulation results show that the error of current measurement is 鈮，

本文編號：1934663