How Does A Fish Finder Transducer Work? Important Guide

Fish finders are gadgets that are meant to identify fish under water. They do this by changing electrical pulses into acoustic energy or sound waves. A transducer is simply the sonar area of the fish finder. It takes signal into the water, and then locates any echo to inform you where the fish are.

People no longer dangle their poles and lines and hope for the best. Clearly, this device is very important. High quality fish finder transducers have a better chance of understanding signals. Therefore, consider getting a fishfinder with the best transducer. 

How Does A Fish Finder Transducer Work

Basic Theory and Most Common Types of Transducers 

In order to understand how transducers work, it’s important to keep the following factors in mind. Hopefully, you’ll have easier time identifying with these all-important devices.

Higher frequency transducers

They have a short wave length and many wave cycles per second. This means you can see many details but very shallow to in depth capacity. It can detect a quarter inch fish. High frequency shows a clear picture of the bottom but less depth range. 800 kHz or 455 kHz transducers work best.

Lower frequency transducers

This one has longer waves but fewer waves per second. It displays less details but contain more energy hence can maneuver to greater depths. It only detects fish with large air bladders. They not show clear pictures but will function well in ocean depths.

Dual frequency transducers

This one uses a similar piezoceramic element for sending and receiving pulses of many frequencies.

Dual beam or Quadra beam

Transducers use many elements. Lower frequencies use wider beams to help in finding larger objects. High frequencies allow you to zoom on the fish below your boat.

Another great content of us: 10 Best Places to go Fishing in San Antonio: A Handy Reference Guide

What happens in the making of a transducer?

The most important component of a transducer is a piezoceramic element. This part converts electrical pulses into sound waves. It also coverts sound waves back to electrical energy when echoes return. They are mainly found in form of a disk. A transducer can have one element or many elements called an array.

A transducer comprises of the following components:

  • Piezoceramic element
  • Cable
  • housing
  • Acoustic window
  • Encapsulating material
  • Sound absorbing material

How a fish finder transducer works

Here’s a simple way of understanding a how a transducer operates. Think of it as a microphone and a speaker made in single unit. A transducer gets a sequence of transmit pulses from an echo sounder.It then changes the pulses into sound.

The sound then goes via water in form of pressure waves.  When the waves hit an item like fish it immediately bounces back. Wave echoes Just like your voice echoes off a wall. The transducer gets sound waves during the time of every transmit pulse. It changes sound waves to electrical energy.

Transducers use   most of their   time listening to echoes and little time transmitting.  The echosounder calculates the time difference in transmitting a pulse and echo return. It shows the information on the user’s screen an understandable manner.

Is a fish able to hear the sound waves emitting from a transducer?

Not really, the sound waves produced are normally ultrasonic. Frequency refers to the amount of vibrations that happen in a particular time period. Most fish cannot hear frequencies above 500 Hz. Human may hear frequencies from 10 Hz to 20 kHz.

Transducers send sound waves with frequencies of between 10,000 kHz to 2 MHz. This is far beyond the hearing of fish.

How the transducer is able to identify a fish

A transducer is able to see a fish by sensing the air bladder. Each fish possesses an organ by known as an air bladder.  It is contains gas that enables fish to adapt to water pressure in various depths. The gas amount in the fish can be reduced or increased to control the fish buoyancy.

The air bladder has a different density than bone or flesh. This difference makes the sound waves coming from the echosounder bounce off the fish. The transducer will finally receive echoes. The echosounder recognizes these differences and shows it as a fish

Also read: Beginners Fishing Guide: Important Advice for You

Various Transducers mounting styles for your boat

In the hull mount

Threaded bronze or stainless steel shaft goes through a hole in the surface hull. They are the most difficult to install but they give the best signal quality. They work with any type of engine. They perform well on sailboats and power.

Thru hull tilted element mount

They transducers mount via a hole drilled in metal or fiberglass. The components are tilted to match the hull’s dead rise. This ensures that the sonar beam points straight down. They allow smooth flow of water over the hull hence less impact on boat performance.

Thru-hull with fairing

These popular transducers are mounts on a stem. The transducer stretches beyond the hull surface in a fairing block. They offer the most accurate and reliable sonar performance. However, they can negatively affect the boat’s speed and fuel efficiency.

Transom mount

These ones are fixed to your vessel’s stern where there is smooth water flow. It is simple to install and maintain and don’t require drilled holes below the waterline. The transducer can be easily adjusted for transom angle compensation.

When installed in a good location, they can be highly reliable with minimal effect on the performance of the vessel.

Chest mount

They are installed in a small box connected to the outside vessel. A tiny hole is drilled in the hull to allow the cable to enter through a stuffing tube. Chest mount transducers have a great effect on vessel performance. They are not suitable for high-speed boats.

Pocket /keel mount

These transducers are installed in a custom pocket in the vessel’s hull.  In most cases they are mounted in vessels. Whereby, a proper pocket is provided by the boat manufacturer. They provide accurate and reliable sonar performance. They have an impact on fuel efficiency and boat’s speed.


It is important to choose the best transducer to match your boat. Based on your type of fishing, consult the seller on the best transducer. This will definitely make your fishing experience worthwhile.

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