Hydrophones and Acoustic Receivers





Hydrophones are underwater listening devices that convert sound into electrical signals and amplified for playback over speakers and/or recorded for later use. Hydrophones be utilized for both passive monitoring of sound or targeted to specific amplitudes and frequencies of sound. Acoustic receivers have data recorder in addition to a hydrophone for remote monitoring systems.

How it worksEdit
 Most modern hydrophones use a piezoelectric material, such as quartz to detect sound 1. Piezoelectric materials become charged when exposed to physical stress such as pressure changes2. By measuring the electrical output generated by the crystal, the pressure changes of sound waves can be identified. Alternatively electrical charge can be delivered to the piezoelectric material causing it to vibrate2. As the pressure exerted on the material increases, the amount of charge needed to maintain the exited state increases. Therefore, pressure changes of sound waves can also be detected by measuring the amount of electricity needed to maintain the vibration of the piezoelectric material.

 Sensor Variations Edit Hydrophones can be omnidirectional, detecting sound striking it from any direction with equal sensitivity or directional, detecting sound originating from a specific direction with higher sensitivity.

External LinksEdit
1http://www.dosits.org/science/soundmeasurement/measure/

2http://hyperphysics.phy-astr.gsu.edu/hbase/solids/piezo.html

