How do your depth sounders and fish finders work?

fish finders use SONAR. The word "sonar" is an abbreviation for "SOund, NAvigation, and Ranging". It was developed as a means of tracking enemy submarines during World War II. A sonar consists of a transmitter, transducer, receiver, and display. In the simplest terms, an electrical impulse from a transmitter is converted into a sound wave by the transducer and sent into the water. When this wave strikes an object, it rebounds. This echo strikes the transducer, which converts it back into an electric signal, which is amplified by the receiver and

sent to the display. Since the speed of sound in water is constant (approximately 4800 feet per second), the time lapse between the transmitted signal and the received echo can be measured and the distance to the object determined. This process repeats itself many times per second. Although these frequencies are in the sound spectrum, they’re inaudible to both humans and fish.