如果您拥有的增益单元的增益能 够用简单的电位器平滑地从正 变成负,那么,这迟早会派上用 场。所示的电路利用R2电位器实现了这个功能(图1)。运算放大器A1接成差分放大器,其两个输入端连接在一起。 Sooner or later it will come in handy if the gain of your own gain cell can smoothly change from positive to negative with a simple potentiometer. The circuit shown uses the R2 potentiometer for this function (Figure 1). Operational amplifier A1 is connected as a differential amplifier, the two inputs are connected together.