A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

TLDR: In this article, an experimental setup that can simultaneously measure the absolute dissipation factor and the resonant frequency of a short-circuited quartz crystal microbalance is described, where the crystal leads are fed through the center of the ferrite toroid and the secondary winding of the transformer is connected to a digitizing oscilloscope which records the decay of the crystal oscillation.

Abstract: An experimental setup is described that can simultaneously measure the absolute dissipation factor and the resonant frequency of a short‐circuited quartz crystal microbalance The crystal is driven at approximately its resonant frequency by a signal generator which is intermittently disconnected by a relay, causing the crystal oscillation amplitude to decay exponentially The decay is measured using a ferrite toroid transformer One of the crystal leads is fed through the center of the ferrite toroid and thereby acts as the primary winding of the transformer The secondary winding of the transformer is connected to a digitizing oscilloscope which records the decay of the crystal oscillation From the recorded decay curve, the absolute dissipation factor (calculated from the decay time constant) and the series resonant frequency of the freely oscillating crystal are obtained Alternatively, the dissipation factor and resonant frequency can be measured for the crystal oscillating under open‐circuit conditions, ie, in the parallel mode The measurements are automated