Accelerometer is a device which measures the acceleration of an object. We use IEPE type accelerometers to measure the acceleration particularly in shock and vibration tests and in structure-borne noise measurement.
Simply; IEPE (Integrated Electronics Pizeo-Electric) type accelerometers includes a seismic mass which is connected to a piezoelectric crystal. When the accelerometer is accelerated, the acceleration causes an inertial force on the seismic mass. That inertial force creates a mechanical stress in the piezoelectric crystal which causes an electrical potential difference between two sides of the crystal. The changes in electrical potential difference creates the electrical signals which then be converted to acceleration information in apropriate units by multiplying its magnitude with the sensitivity of the accelerometer.