Bernard D.H. Tellegen[1] (24 June 1900 – 30 August 1990) was a Dutch electrical engineer and inventor of the pentode and the gyrator.

In the period 1946–1966, Tellegen was an adjunct professor of circuit theory at the University of Delft.

The Australian Institute of Radio Engineers appointed Tellegen an honorary life member in 1953.

Tellegen was elected a member of the Royal Netherlands Academy of Arts and Sciences in 1960.

[3] In 1970, the University of Delft conferred him a doctor honoris causa degree.