Theoretical study of the vibrating capacitor method

Suppose we have a plane capacitor, whose section area is denoted by S and whose electrodes are lo apart from each other and made of solids R and S. Its capacitance Co is  

8 represents the dielectric constant of the medium between the two electrodes. 

When an electrode is moved according to a sinusoidal law of amplitude h and (mechanical) pulsation co, the distance between electrodes 1 varies as a function of time according to  

Under such conditions, the capacitor s capacitance C equals  

At low modulation amplitudes, that is to say when m 1, we will assume the following expression for C  

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