Bernardus Dominicus Hubertus (Bernard) Tellegen

Influential inventor at Philips and esteemed professor in Delft

Bernard Tellegen graduated in 1923 as an engineer in electrical engineering. He exchanged the Delft University of Technology for the Philips Physical Laboratory and became Balthasar van der Pol’s first employee. After several years of research focused on triodes, he invented the pentode in 1926. This radio tube with five electrodes was used in Philips’ first radio receiver. The pentode was soon used in all new radios and amplifiers.

Tellegen was also strong in theory. He gained much depth in the research into electrical networks, for example through his theory of the gyrator. From 1946 to 1966 he was extraordinary professor of network theory at Delft University of Technology, and in 1970 received an honorary doctorate from Delft.

Besides his work for Philips and Delft University, he was for many years chairman and then honorary member of the Dutch Electronics and Radio Society. He was also chairman of the Dutch URSI Committee from 1948 to 1960. In 1960, he was elected a member of the Dutch Royal Academy of Sciences. Tellegen’s work was crowned in 1973 when he became the first non-American to receive the IEEE Edison Medal. He was praised for his creative career and significant achievement in electrical circuit theory. Tellegen died at the age of 90.