It’s no exaggeration to say that the entire discipline of sound and vibration can be traced to these and other innovations developed by Per Brüel and his partner Viggo Kjær. Located in Nærum, Denmark, Brüel & Kjær started the sound and vibration journey in the distant 1942.
These early innovations created the foundation for the many sound and vibration measurement technologies used to develop and monitor everything from smartphones, cars, washing machines and aircrafts, we use today.
From a humble start with a small, voltmeter product line, Brüel & Kjær quickly expanded the product range over the years, which today consists of over 200 measuring instruments, transducers, and analysis software.
Accelerometer Innovation Since 1942
Type 4301 was only the first in a long line of world's first innovative technologies to be released, but before we get to how the first commercial accelerometer ever made, let's take a closer look at some of the many technology innovations, that Brüel & Kjær has developed.
The table below gives a complete overview of the ground-breaking technological inventions, which are still used in test and measurement applications world-wide.
The World's First Commercial Accelerometer
In the year 1943, Per V. Brüel designed the world’s first commercial piezoelectric accelerometer called Type 4301. It was made from Rochelle salt crystals and featured a sensitivity of 35–50 mV/g and a resonant frequency of 2–3 kHz.
On the left: Prototype drawings of Type 4301. On the right: Photo of the actual accelerometer.
Throughout the 1950s the Rochelle salt crystals were replaced by ceramic elements. This resulted in a doubling of the accelerometer’s sensitivity and increased its resonance to 5kHz.
Later, Brüel & Kjær added compression type accelerometers to its product line, which were further modified in 1964. This resulted in the introduction of a new series with reduced susceptibility to case loading and base strain. Further improvements in the compression design were made from 1968 to 1975.
Transducer development and innovation is very much in the Brüel & Kjær DNA. Today, we lead the industry with our many patented technology and unrivalled accuracy.