Accelerometers are sensors and instruments for measuring, displaying and analyzing acceleration and vibration. They can be used on a stand-alone basis, or in conjunction with a data acquisition system. Accelerometers are available in many forms. They can be raw sensing elements, packaged transducers, or as a sensor system or instrument, incorporating features such as totalizing, local or remote display and data recording. Accelerometers can have from one axis to three axes of measurement, the multiple axes typically being orthogonal to each other. These devices work on many operating principles. The most common types of accelerometers are piezoelectric, capacitance, null-balance, strain gage, resonance, piezoresistive and magnetic induction.