在上题电路中若将R_B改成22kΩ，并且要求得到∆V_T=2.5V，试计算RA的取值应当是多少。

A．<img src='https://img2.soutiyun.com/ask/uploadfile/5451001-5454000/47b2a510e0a9d766936e559a75f13cc6.jpg' /> B．<img src='https://img2.soutiyun.com/ask/uploadfile/5451001-5454000/ba7c4c26f9e0aabf45a5288979363c3b.jpg' /> C．<img src='https://img2.soutiyun.com/ask/uploadfile/5451001-5454000/b741de6e39726b6e8d48e6783572fa50.jpg' /> D．<img src='https://img2.soutiyun.com/ask/uploadfile/5451001-5454000/df5c3cc12ef18067afdb65ba624ba90f.jpg' /> <img src='https://img2.soutiyun.com/ask/uploadfile/5451001-5454000/725c8102fac358252108dc862a676ffc.jpg' />

A．16V，17Ω B．16V，9Ω C．-16V，10Ω D．-16V，9Ω <img src='https://img2.soutiyun.com/ask/uploadfile/5484001-5487000/d82841b01f81c0fd530f8efa2a7ceb0b.png' />

<img src='https://img2.soutiyun.com/shangxueba/ask/18090001-18093000/18091138/2015102715483287833.jpg' /> A．-1V，5.143Ω B． 1V，5Ω C． -1V，5Ω D． 1V，5.143Ω

在图4.4.1(a)和(b)所示的互补对称电路中，已知Vcc=6V，R_L=8Ω，假设三极管的饱和管压降U_CES=1V。 ①试估算电路的最大输出功率P_om; ②估算电路中直流电源消耗的功率P_V和效率η。 并将两个电路的估算结果进行比较。 <img src='https://img2.soutiyun.com/ask/2020-09-10/968622476866462.png' />

在图2.4.3所示的射极输出器电路中，设三极管的β=100，Vcc=12V，R_e=5.6kΩ，R_b=560kΩ，r_bb’=300Ω。 ①求静态工作点; ②分别求出当R_L=∞和R_L=1.2kΩ时的 <img src='https://img2.soutiyun.com/ask/2020-09-10/96862189830037.png' /> ③分别求出当RL=∞和RL=1.2kΩ时的Ri; ④求R0。 <img src='https://img2.soutiyun.com/ask/2020-09-10/968621904984752.png' />

电路如图题4-6(a)所示，u_S=12V、R=2kΩ，网络N的VCR如图题4-6(b)所示，求u和i，并求流过两线性电阻的电流。 <img src='https://img2.soutiyun.com/ask/2020-08-27/967409762293118.png' />

A．6A B．4A C．3A D．2A

<img src='https://img2.soutiyun.com/ask/2020-09-17/969200956020412.png' />

<img src='https://img2.soutiyun.com/ask/2020-11-30/975580651375764.png' />

<img src='https://img2.soutiyun.com/ask/2020-10-21/972145930727238.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-11-27/975340297126786.png' />

<img src='https://img2.soutiyun.com/ask/2020-09-14/968968410198828.png' />

A．80&Omega; B．8&Omega; C．0.8&Omega; D．800&Omega;

<img src='https://img2.soutiyun.com/shangxueba/ask/50796001-50799000/50796740/967040986097027.png' />

<img src='https://img2.soutiyun.com/ask/2020-09-01/96781572451352.png' />

设向量组B：b₁，b₂，…，b_r能由向量组A：a₁，a₂，…a_r线性表示为(b₁，b₂，…，b_r)=(a₁，a₂，…，a_r)K，其中K为s×r矩阵，且A组线性无关。证明B组线性无关的充要条件是矩阵K的秩R(K)=r。

在图NT6-4所示锁相解调电路中，若将环路滤波器改为简单RC滤波器，则当环路的输入信号v_i(t)=V_imsin(ω_rt+M_fsin_Ωt)时，试证:为实现不失真解调，必须满足下列关系式<img src='https://img2.soutiyun.com/ask/2021-02-26/983187125725284.png' /> <img src='https://img2.soutiyun.com/ask/2021-02-26/983187147945554.png' />

求题2.25图所示电路中A、B端口的等效电阻。已知R₁=2Ω;R₂=12Ω,R₃=5Ω,R₄=8Ω,R₅=10Ω,R₆=14Ω。 <img src='https://img2.soutiyun.com/ask/2020-10-07/970904454837801.png' />

<img src='https://img2.soutiyun.com/ask/2021-01-21/980073358567216.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-11-16/97440849814341.png' />

分别判断图P2.2(a)、(b)所示两电路各属哪种放大电路,并写出Q、A_u、R_i和R₀的表达式. <img src='https://img2.soutiyun.com/ask/2021-01-09/979034368257886.png' /> <img src='https://img2.soutiyun.com/ask/2021-01-09/979034378158452.png' />

电路如图6-2(a)所示，图(b)为电感电压的波形图，已知R=10Ω，L=4 H，电感电流i_L(0)=0，求电流i_L(t)。 <img src='https://img2.soutiyun.com/ask/2020-08-23/967073690265931.png' />

(1)计算静态值I_B，I_c，U_cE; (2)画出微变等效电路，求两个输出端的电压放大倍数<img src='https://img2.soutiyun.com/ask/2020-11-15/974326186869807.png' /> (3)求该电路输入电阻ri和两个输出端的输出电阻r₀₁和r₀₂ (4)如果输入信号是正弦信号，试对比输入信号定性画出输出电压u₀₁及u₀₂波形; (5)找出电路的反馈元件，如果从集电极输出电压，属何种类型反馈？如果从发射极输出电压，属何种类型反馈？ <img src='https://img2.soutiyun.com/ask/2020-11-15/974326193406181.png' />