A simple method for detecting very small changes in capacitance or inductance is presented. In the circuit used in the proposed method, which employs LC resonance, the phase of the output signal sharply and monotonically changes by about 180° around the resonance frequency. When the capacitance or inductance changes slightly, the resonance frequency shifts accordingly. This change can be sensitively detected as a phase shift of the output signal by applying a fixed frequency signal to the circuit near the resonance frequency. The circuit used for detection is entirely composed of general-purpose electronic components and does not use special function devices. This method can be applied in various practical contexts, for example, object detection, proximity sensing, monitoring material properties, and electric capacitance tomography.

提出了一种检测电容或电感的很小变化的简单方法。在所建议方法中使用LC的电路中共振时，输出信号的相位在共振频率附近急剧单调变化约180°。当电容或电感稍有变化时，谐振频率就会相应地移动。通过将固定频率的信号施加到谐振频率附近的电路，可以灵敏地将此变化检测为输出信号的相移。用于检测的电路完全由通用电子组件组成，不使用特殊功能的设备。该方法可以在各种实际情况下应用，例如，物体检测，接近感测，监视材料特性以及电容层析成像。