【正文】 一步驗證了電路理論設(shè)計的正確性和可行性。 基于 OPA842ID，本設(shè)計介紹了小信號放大電路的探究與設(shè)計。它不僅使我們的日常生活更加豐富多彩，而且對經(jīng)濟、國防等做出了不可磨滅的貢獻。然而小信號有它自身的缺陷，由于它本身的能量較小，容易被噪聲淹沒或受到外界的干擾 ，而且對小信號放大電路設(shè)計的難處主要在高性能運算放大器。該電路由五個OPA842ID 組成的輸入級差分放大電路、中間級電壓放大電路和輸出級功率放大電路完成對小信號的采集、電壓放大和功率放大。 關(guān)鍵詞 ： 小信號 放大電路 OPA842ID Multisim 第 2 頁 Abstract Currently, the application of the small signal circuit is extremely wide, small to speakers, radios and other civilian industry, large to satellites, rockets and other military industry. It not only makes our daily life more colorful, but also made an indelible contribution to the economic, defense and others. However, the smallsignal has its own flaws, because of itself smaller energy, it is easy to drown by the noise or interference by outside. And the main difficulty of small signal amplification circuit design is highperformance operational amplifier. The pros and cons of the operational amplifier performance determine the performance of the circuit. Compared with foreign countries, the domestic operational amplifier is relatively backward, lead to the study of the smallsignal amplifier circuit in a backward state. Based on OPA842ID， this design introduces a small signal amplification circuit of inquiry and design. The circuit is posed by five OPA842ID input level differential amplifier circuit, the intermediate stage voltage amplifying circuit and the output stage power amplifying circuit to plete the acquisition of the small signal, the voltage amplification and power amplification. At the same time, it effectively suppresses or eliminates the temperature drift of the circuit and the monmode signal, making the amplified signal distortion smaller. After pleted the circuit design, using Multisim circuit simulation software to simulate. By applying a sinusoidal voltage signal， from the quiescent operating point of the circuit analysis, AC analysis and so on to simulation, to draw the simulation results of the voltage gain, bandwidth, etc, further validate the correctness and feasibility of the circuit theory design. Key words ： Small Signal Amplifier circuit OPA842ID Multisim 第 3 頁 目 錄 第一章 緒論 .................................................. 5 本課題的背景及意義 ................................................ 5 本課題的主要研究內(nèi)容 .............................................. 5 第二章 小信號放大電路的系統(tǒng)方案 ............................... 6 系統(tǒng)方案介紹 ...................................................... 6 系統(tǒng)框圖 .......................................................... 6 相關(guān)子模塊的方案論證 .............................................. 6 輸入級差分放大電路 ........................................... 6 中間級電壓放大電路 ........................................... 7 輸出級功率放大電路 ........................................... 8 第三章 常見的問題及解決方法 .................................. 9 電源電壓波動 ...................................................... 9 電源電壓波動對電路的影響 ..................................... 9 解決方法 .................................................... 10 溫度變化對電路中各元器件的影響及解決方法 ......................... 10 溫度對電阻阻值的影響及解決方法 .............................. 10 溫度對運放參數(shù)及特性的影響及解決方法 ........................ 12 運放輸入偏置電流對電路的影響及解決方法 ........................... 13 電路負載特性及解決方法 ........................................... 14 第四章 小信號放大電路的設(shè)計 ................................. 16 信號的采集 ....................................................... 16 電壓放大倍數(shù) Av1 ............................................. 16 帶寬分析 .................................................... 17 信號的放大 ....................................................... 18 電壓放大倍數(shù) Av2 ............................................. 18 帶寬分析 .................................................... 18 信號的功率放大 ................................................... 19 電壓放大倍數(shù) Av3 ............................................. 19 帶寬分析 ........................................