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试题名称:电子线路一、问答题:1.图1为串联型基本稳压电路。为了提高该稳压电路输出电压 V_0的稳定性,图中有关元器件的性能和参数应该如何选择? (8分)2.当输出功率为50W 以上时,在负载电阻很大(30Ω以上)或者很小(4Ω以下)的条件下,往往不采用无变压器乙类功率放大电路而采用有输出变压器的乙类功率放大电路。试问这是为什么? (8分)3.为什么调谐放大器中会出现不稳定的问题?要解决此问题有哪些途径? (8分)4.调频广播主要工作在什么频段?为什么? (6分)二、图2为共漏-共发两级混合放大器,请画出中频时的等效电路,并计算中频时的电压放大倍数 A_(VS)。已知元器件参数如下:R_S=1kΩ;R_(?)=2MΩ;R_1=2kΩ;R_2=30kΩ;R_3=20kΩ;R_C=3kΩ;R_L=600Ω。T_1为 N 沟道结型场效
Question Name: Electronic Circuit First, the question and answer questions: 1. Figure 1 is a series of basic voltage regulator circuit. In order to improve the stability of the voltage regulator circuit output voltage V_0, the figure on the performance of the components and parameters should be how to choose? (8 points) 2. When the output power of 50W or more, the load resistance is very large (30Ω above) or Small (4Ω below) conditions, often do not use transformerless B power amplifier circuit with output transformer B power amplifier. (8 points) 3. Why is there an unstable problem in the tuned amplifier? What are the ways to solve this problem? (8 points) 4. What is the main frequency band for FM broadcasting? Why? (6 points) Second, Figure 2 shows a common-leakage-common-mode two-stage hybrid amplifier. Please draw the equivalent circuit of IF and calculate the voltage amplification A_ (VS) at IF. The component parameters are as follows: R_S = 1kΩ; R_ (?) = 2MΩ; R_1 = 2kΩ; R_2 = 30kΩ; R_3 = 20kΩ; R_C = 3kΩ; R_L = 600Ω. T_1 is the N-channel junction field effect