My first post here. :D usually this situation does not arise, but I am working on thin piezoelectric films. When a apply a alternating voltage on the electrodes, the film vibrates. Now this constitutes a LCR circuit which has a resonant and anti-resonance frequency. Since it is vibrating, it will have a mechanical resonant frequency at which the amplitude of vibration will be maximum. Obviously, the frequency of vibration will be determined by the frequency of the applied alternating voltage. What I don't understand is this, is there any relation between the electrical and mechanical resonant frequencies? Or can the electrical and mechanical resonance conditions be achieved at the same applied frequency. Please correct me if there is any fundamental mistake in my reasoning.