When the mounting surface of a single-axis accelerometer is setup with a downward direction, + voltage* is output when the sensor is accelerated with upward, and – voltage is obtained when the sensor is accelerated with downward.

 

For example, mount the accelerometer on the horizontally-located board and swat it from under surface with upward acceleration. The sensor outputs +voltage* first since the board have acceleration with upward first. The tri-axial accelerometer has polarity indication on its body by "arrows".

 

*: +charge is output when the charge output type is used.

 

 

Attention

 

 Some of the charge amplifiers have polarity which is inverted (180 degree) in amplifier. Please flip an accelerometer with finger tip and check the output polarity.