How do hydrophones work

Just as a microphone collects sound in the air, a hydrophone detects acoustic signals under the water. Most hydrophones are based on a special property of certain ceramics that produces a small electrical current when subjected to changes in underwater pressure.

1. How far can hydrophones hear?
2. Are hydrophones still in use?
3. What is measured when using a hydrophone?

How far can hydrophones hear?

Using an underwater microphone called a hydrophone, a second boat stationed 900 miles away successfully detected the sounds. Subsequent tests picked up the signal at a distance of 3,000 miles.

Are hydrophones still in use?

From late in World War I until the introduction of active sonar in the early 1920s, hydrophones were the sole method for submarines to detect targets while submerged; they remain useful today.

What is measured when using a hydrophone?

Hydrophones are designed to measure the mechanical sound pressure in water. Most hydrophone sensors are piezoelectric materials which convert mechanical energy to electrical energy.