The World’s first commercial piezoelectric accelerometer was developed by Dr. Per V. Brüel in 1943. This was only the first of many innovations, that would shape the world of test and measurement, we know today. Explore the great history of the piezoelectric accelerometer, and the many innovations that followed, solidifying Brüel & Kjær as the the primary source of sound and vibration measurement technology.
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.
1943
Type 4301
World’s first commercial piezoelectric accelerometer made from Rochelle salt crystals and developed by Dr. Per V. Brüel in 1943.
A strong piezoelectric effect was discovered in lead zirconate titanate (PZT) by Jaffe in the early of 1950s, leading to the release of Brüel & Kjær’s first lead zirconate titanate (PZT) accelerometer
1971
Type 8305
Brüel & Kjær’s standard reference accelerometer based on an inverted, centremounted compression design with quartz crystal piezoelectric element, ensured a high degree of accuracy for calibration
This all‐titanium accelerometer was the first based on Brüel & Kjær’s patented DeltaShear™ design. Still in use today, the construction is regarded as one of the all‐time, classic accelerometer constructions
Brüel & Kjær’s first and highly reliable industrial DeltaShear accelerometer suitable for permanent vibration monitoring in potentially explosive environments
A ThetaShear™, CCLD accelerometer for applications up to 180 °C (356 °F) – the highest temperature for an accelerometer with built‐in preamplifier in the industry
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.
LEARN MORE
