复习Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.第二章 放大电路的基本原理 2.1 放大的概念和放大电路的主要技术指标2.2 单管共发射极放大电路 2.3 放大电路的基本分析方法 2.4 工作点的稳定问题 2.5 放大电路的三种基本组态 2.6 场效应管放大电路Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2.1 放大的概念和放大电路的主要技 术指标本质：实现能量的控制和转换。放大作用：小能量对大能量的控制作用。放大的对象是变化量。元件：双极型三极管和场效应管。2.1.1 放大的概念Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2.1.2 放大电路的主要技术指标一、放大倍数二、最大输出电压uO无明显失真情况下负载可得到的最大输出电压Uom 。三、非线性失真系数 D 所有谐波总量与基波成分之比，即四、输入电阻 Ri输入端看进去的等效电阻 。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.五、输出电阻 Ro从输出端看进去的等效电阻 。实验室测法：Ro愈小，带载能力愈强。分别测量空载和带载 RL 的 、 。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.六、通频带七、最大输出功率与效率输出无明显失真的最大输出功率（Pom）。 ：效率 PV：直流电源消耗的功率AumBWfL fHfL：下限频率fH：上限频率Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2.2 单管共射放大电路2.2.1 单管共射放大电路的组成VT：三极管，放大元件；VCC：能源；RC：将iC的变化转化为uO的变化,传送到输出；VBB 、RB：为发射结提供正偏电压,提供静态IB。VCCRBVBBRCVT+ ui+ uo+iCiBEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.单管共射放大电路的放大作用VCCRBVBBRCVT+ ui+ uo+iCiBEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.三、设置静态工作点的必要性输出电压必然失真！设置合适的Q点，解决失真问题！为什么放大的对象是动态信号，却要晶体管在信号为零 时有合适的直流电流和极间电压？Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2.2.2 设置静态工作点的必要性什么是静态工作点？1. Q点过低 截止失真ibui首先 iB 波形失真OQOttOuBE/ViB / AuBE/ViB / AIBQEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.四、基本共射放大电路的工作原理饱和失真截止失真底部失真顶部失真动态信号 驮载在静 态之上输出和输入反相 ！要不失真，就要 保证晶体管始终 工作在放大区！波形分析Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.静态工作点Q的计算ICQ IBQUCEQ = VCC ICQ RCVCCRBVBBRCVT+ ui+ uo+iCiBEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.五、放大电路的组成原则 Q点合适：合适的直流电源、合适的电路参数 。 输入信号能有效加在发射结上，输出信号有效 加在负载上。 共地、电源种类尽量少、负载上无直流分量。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.两种实用放大电路 直接耦合放大电路问题： 1. 两种电源 2. 信号源与放大电路不“共地”将两个电源 合二为一共地，且要使信号 驮载在静态之上静态时，动态时，b-e间电压是uI与 Rb1上的电压之和。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.两种实用放大电路 阻容耦合放大电路耦合电容的容量应足够 大，即对于交流信号近似 为短路。其作用是“隔离 直流、通过交流”。静态时，C1、C2上电压？CEQC2BEQC1UUUU=，动态时，C1、C2为耦合电容！ UBEQ UCEQuBEuIUBEQ，信号驮载在静态之上。负载上只有交流信号。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.单管共射放大电路的波形分析Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.讨论1