Vibration Sensors - Accelerometers
Accelerometers are used for measuring vibration and shock on machines and basically anything that moves. Their outputs can also be integrated and double-integrated to calculate displacement and velocity.
Accelerometers for making dynamic measurements are normally based on the piezoelectric principle: when a quartz crystal is put under stress it releases a stream of charged ions proportional to the stress. These charge sensors are connected to a charge type signal conditioner. An even more popular type is IEPE sensors, which have an integrated pre-amplifier, and which require a less expensive signal conditioner.