Accelerometer

Synonyms

Geophone; Gravimeter

Definition

An accelerometer is defined as a transducer whose output is proportional to acceleration.

An accelerometer measures the proper acceleration it experiences relative to freefall. This is equivalent to inertial acceleration minus the local gravitational acceleration, where inertial acceleration is understood in the Newtonian sense of acceleration with respect to a fixed reference frame, which the Earth is often considered to approximate.

An accelerometer can be used for detecting magnitude and direction of the acceleration as a vector quantity.

An accelerometer consists of a proof mass, a reference frame, a sensor (an induction coil or a potentiometer and so on), a spring, a damper, and a casing. Because of the constraint of the reference frame, the proof mass can only move along an axis-line. According to Newton’s law, when the casing experiences an acceleration in the axis, the proof mass with a certain inertia resists a change in its state of...