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试题名称:电子电路一、计算下列各题:1.某放大电路的直流简化电路如图1所示,晶体管 BG 的直流放大系数β为50,且工作于放大区。试近似求出 BG 的基极电流 I_B,集电极电流 I_C,集电极至发射极之间的电压 V_(CE)。2.图2(a)为用理想运算放大器组成的电路(略去了各运算放大器同相输入端的直流平衡电阻)。若 u_1(t),u_2(t)的波形如图2(b)所示,试画出 u_0(t)的波形。3.图3为集成运算放大器中某一级的原理电路,各管直流放大系数β都很大(BG_1、BG_2的基极直流接地)。试近似求恒流管 BG_3的电流 I_0。二、某负反馈放大器的交流简化电路如图4所示。已知:h_(ic1)=h_(ie2)=1.5kΩ;h_(fe1)=h_(fe2)=50;h_(oe1)=h_(oe2)=0;h_(re1)=h_(re2)=0;R_8=300Ω;R_(c1)=1.2kΩ;R_(e1)=300Ω;R_(c2)=1kΩ;R_f=2.3kΩ。求电路的电压放大系数 K_(vf)=V_0/V_(?)
Title: Electronic Circuit First, calculate the following questions: 1. A simplified circuit DC amplifier circuit shown in Figure 1, the transistor BG DC amplification factor β is 50, and work in the amplification area. Try to approximate the BG base current I_B, collector current I_C, collector to emitter voltage V_ (CE). 2. Figure 2 (a) shows the circuit using an ideal op-amp (omitting the DC balance resistor at the noninverting input of each op amp). If u_1 (t), u_2 (t) of the waveform shown in Figure 2 (b), try to draw u_0 (t) of the waveform. 3. Fig. 3 is the principle circuit of a certain level in the integrated operational amplifier, the direct current amplification coefficient β of each tube is very great (BG_1, BG_2’s base direct current is grounded). Try approximation to find the current I_0 constant current tube BG_3. Second, a negative feedback amplifier to simplify the circuit shown in Figure 4. It is known that h_ (ic1) = h_ (ie2) = 1.5kΩ; h_ (fe1) = h_ (fe2) = 50; h_ (oe1) = h_ (oe2) = 0; h_ (re1) = h_re2 = 0; R_8 = 300Ω; R_ (c1) = 1.2kΩ; R_ (e1) = 300Ω; R_ (c2) = 1kΩ; R_f = 2.3kΩ. Find the circuit voltage amplification factor K_ (vf) = V_0 / V_ (?)