Transducers / Sensors by Brüel & Kjær


Transducers are a core part of Brüel & Kjær’s business and have been for more than 70 years. The quality of our products is renowned worldwide and is the result of our unique experience and knowledge in the production, development of our products. Each transducer is subject to meticulous testing and quality control, ensuring you get the industry-leading accuracy, performance, and stability across any application.

What is a transducer



Transducers are a core part of Brüel & Kjær’s business – they always have been, for more than 60 years. 



Brüel & Kjær continually invests in state-of-the-art transducer production and test equipment



Each transducer is subjected to between five and ten test functions during its manufacture




The parameters of prototypes are thoroughly tested and verified against the FEM model and the requirement specification



After the production process is completed, the key parameters of every accelerometer are 100% tested to check that its performance is within specification



Many companies produce transducers but it is our attention to testing and quality control at all stages of the production process that makes the difference



Brüel & Kjær is accredited to ISO 9001 and EN 9100


A transducer is a device that converts electrical signals (energy) from one form to another in such a manner that the desired characteristics of the input energy appear at the output signal.

Transducers are a vital first link in your measurement chain.

Whether you measure electrical signals or high-frequency acceleration or sound waves, they stand on the front line and provide you with the full scale of raw data needed for making critical decisions. It is absolutely vital that the data is trustworthy and provides real insights.

Transducer applications range from the development of quieter, safer cars, to ensure that an aircraft and its engines are totally reliable and environmentally friendly and that household appliances have low levels of noise and vibration.

The types of transducers and their applications are almost endless - and so is the wide range of Brüel & Kjær transducer types. From industry-leading measurement microphones, and hydrophones, to sound sources for acoustic measurements, to force transducers, impact hammers and our extensive range of piezoelectric accelerometers with patented technology.


The terms transducer and sensor are often used interchangeably – but in fact, they can be very different devices and possess different characteristics.

While both a sensor and a transducer in many cases respond to a physical phenomenon (for example, temperature, pressure, vibration) and provide a signal that can be measured, typically an electrical signal, a transducer can take an electrical signal and convert it to a physical signal (for example, a speaker).

  • A sensor is a more generic term, and may be used to describe an entire ‘system’ for documenting a physical phenomenon (like a thermometer), or just the sensing part of a bigger system ( like photosensors in a camera).
  • A transducer, however, is more narrowly defined as a device, which responds to changes in a physical phenomenon and converts it into a measurable electrical phenomenon, or the inverse.

Transducer sensitivity can be stated in electrical quantity/physical parameter (for example, Picocoulomb/m/s2) or physical parameter/electrical quantity (such as Pascals/Volt).

Our sister company, HBM Test and Measurement, delivers market-leading sensors
such as; strain gauge sensors, optical sensors, and pressure sensors, for variety of applications.




Brüel & Kjær has invented many of the technologies used in most today’s accelerometers and microphones. It is our firm conviction that technology has no limits. If we can imagine it, we can develop it.

In production, every Brüel & Kjær transducer is thoroughly tested to ensure that its performance is within the specified parameters. All components, whether from sub-suppliers or manufactured within Brüel & Kjær, are subjected to rigorous inspection. The inspection takes the form of physical and dimensional control systems to ensure conformity to specifications and quality, as reflected in our status as an ISO 9001 and EN 9100 certified company.

With ultrasound, components are inspected and then cleaned in a demineralized water and soap solution. The parts are then dried using compressed air and placed in an oven to remove any traces of humidity. A unique process is then applied to clean the electronic components. On average, we conduct between five and ten separate test procedures together with individual calibration and validation before shipment.

Brüel & Kjær transducer-solutions are produced with utmost care, and tested in extremely harsh environments. You can follow the process in this video showing the making of Type 4966 Free-Field Microphone:   



We perform an individual calibration on each transducer before shipping. Our unique status as the primary Danish standards lab for calibration reduces our traceability steps and uncertainty in measurement sensitivity.

The information we gather when testing and calibrating is detailed in our product datasheets, and provide information on device sensitivity to external inputs together with any additional specifications.

Transducer Calibration / Sensor Calibration

Calibration is done in our own calibration laboratory using a calibration technique based on FFT analysis. This provides the needed resolution to detect certain types of problems that are hard to identify in other calibration systems.



At Brüel & Kjær, we don’t just design, manufacture, and develop transducers. We are in the business of innovation and always have been. Many of our employees are world-renowned experts, frequently speaking at conferences, presenting papers at seminars, and advising on
new standards.

Sometimes a measurement situation requires a solution that cannot be met by existing Brüel & Kjær transducers. To effectively satisfy the needs of our clients, we have a procedure for efficiently handling requests for specialized and customized products.

Minor modifications are handled with ease and at low cost, whereas major or new items requiring substantial engineering will need technical and economic assessment.


For further details of the range, availability, and price of non-standard transducers, please contact your local Brüel & Kjær representative.