对无电感器滤波器的设计者来说,具有高输入阻抗和低输出阻抗的运算放大器比由负阻抗变换器或迴转器构成的电路有许多可取之处。例如,负阻抗变换器用来提供传递函数分母中两大数目之差。这样便生产了所需要的复数极点,但这些复数极点对网络元件的变化是很敏感的,而且也难以用直流稳定网络。如果是单一的迴转器结构,要求电容量的范围是很宽的。虽然迴转器模拟接地电感是容易的,可是要模拟浮置电感就很困难。为了获得高的Q值,必须使用低捐耗的电容 For inductorless filter designers, op amps with high input impedance and low output impedance have many advantages over circuits made up of a negative impedance transformer or gyrator. For example, a negative impedance transformer is used to provide the difference between the two major numbers in the denominator of the transfer function. This produces the required complex poles, but these complex poles are sensitive to changes in network components and it is also difficult to stabilize the network with DC. In the case of a single gyrator structure, the range of required capacitance is very wide. Although the gyrator simulates the ground inductance is easy, it is very difficult to simulate the floating inductance. In order to obtain high Q values, low-cost capacitors must be used