【单选题】听力原文:W: Are these treatments really necessary? They don't seem to help much. M: I'm afraid so, Mrs. Jones. Just be patient and I'm sure you'll see some results soon. Q: Where did this conversation mos...
【简答题】变间隙电容传感器的测量电路为运算放大器电路,如图所示。 C 0 =200 pF ,传感器的起始电容量 C x0 =20pF , 定动极板距离 d 0 = 1.5mm , 运算放大器为理想放大器(即 K →∞, Z i →∞), R f 极大,输入电压 u 1 =5 sinω t V 。 求当电容传感动极板上输入一位移量△ x = 0.15mm 使 d 0 减小时,电路输出电压 u 0 为多少? 变...