Crystal microbalance
A crystal microbalance most often used as a quartz crystal microbalance (QCM), is a piezoelectric bulk acoustic wace resonator (BAW-resonator) which is excited by an alternating voltage. By adding a mass to a microbalance as e.g. by sputtering or evaporation of matter, the resonance frequency of the resonator is changed. The frequency shift can be used to calculate the mass of the film added. Crystal microbalnces are a widely used tool in thin film thickness monitoring

Charge amplifier
Charge amplifiers are electronic components for processing a polarisation signal of a piezoelectric sensor into a processable (often voltage) signal

Measurement chain
A functional unit comprising of sensor and related electronics is a measurement chain. For piezoelectric technology this unit comprises a piezoelectric sensor, charge amplifier and optional a galvanic separation. The measurement chain ends at the interface to the data acquisition or data handling system.

Piezoelectric actuator
The direct piezoelectric effect is often used for so-called actuators. Electrical energy is used for a precisely controlled deformation (contraction or extension) of piezoelectric elements. Applications of this technology include piezoelectric speakers and injectors for diesel engines. In order to enable three dimensional movements several piezoelectric actuators have to be combined.

Piezoelectric effect
The piezoelectric effect can be separated into a direct piezoelectric effect and an indirect or reverse piezoelectric effect. The direct piezo effect summarizes the material properties of generating an electrical polarization under external forces. In contrast, the reverse piezo effect describes the effect of a change in length induced by an applied voltage; this is also called piezostriction

Piezoelectric sensor
Typically, sensors which are based on the direct piezoelectric effect are called piezoelectric sensors. These sensors are used for the determination of diverse physical properties. Most of the sensors are used as piezoelectric pressure sensors, piezoelectric force sensors or piezoelectric accelerometers to mention a few. Strictly, also sensors based on the reverse piezo effect should belong to this group, but many authors summarize those sensors as bulk acoustic wave sensor (BAW sensor) or surface acoustic wave sensor (SAW sensor).

Sensor
The word sensor is derived from the latin word sensus „sense“. It describes a component that can be used for a quantitative or qualitative determination of chemical or physical properties (e.g. pressure, acceleration, force or temperature)