图1所示电路能以反相或非反相模式放大信号。当开关S_1接通而S_2断开时,该电路就起到正规的反相放大器的功能。当S_2接通而S_1断开时,该电路就将信号馈送到运放的非反相输入端,此时,电路就起到非反相放大器的功能。如果S_1和S_2为单片模拟开关,就可以利用数字信号来控制该电路。可以用一只电位器替代开关,实现同样的设想(图2)。滑动片设定在电位器高端,就是选择了反相模式工作,滑动片设定在电位器其他端,就是选择了非反相模式工作。IC_1的线性数字电位器不仅以数 The circuit shown in Figure 1 can amplify the signal in either inverting or non-inverting mode. When switch S_1 is on and S_2 is off, the circuit functions as a normal inverting amplifier. When S_2 is on and S_1 is off, the circuit feeds the signal to the non-inverting input of the op amp. At this point, the circuit functions as a non-inverting amplifier. If S_1 and S_2 are monolithic analog switches, the digital signal can be used to control the circuit. The same idea can be achieved by using a potentiometer instead of a switch (Figure 2). Slide set at the high end of the potentiometer, is to select the reverse mode, slide set at the other end of the potentiometer, is to choose a non-inverting mode of work. The linear digital potentiometers for IC_1 are not only in number