Balthasar van der Pol

Balthasar van der Pol (1889 to 1959) was a Dutch physicist and applied mathematician famous for the non-linear van der Pol equation. Born in Utrecht, he studied physics and mathematics there, worked with John Ambrose Fleming in London and with J J Thomson at the Cavendish Laboratory in Cambridge, and took his doctorate at Utrecht in 1920 with Willem Henri Julius as thesis supervisor. He worked at Teylers Museum in Haarlem, then from 1922 at the Philips Physical Laboratory in Eindhoven, where he became director of scientific radio research, and held the chair of theoretical electricity at Delft from 1938 to 1949. His work covered the propagation of radio waves, non-linear circuits and relaxation oscillations, transient phenomena and operational calculus, the last in a classic text written with Hendrik Bremmer. His equation first appeared in his 1926 article on relaxation oscillation, and he is regarded as a pioneer of non-linear differential equations.