Hendrik van der Bijl

Hendrik Johannes van der Bijl ( born November 23, 1887 in Pretoria, † 2 December 1948 in Johannesburg ) was a scientist and entrepreneur from South Africa.

His doctorate in physics, he acquired in Leipzig. After working as a physics lecturer in Dresden in 1912, he was researcher at AT & T in the U.S.. He developed during the First World War, the first U.S. miniature electron tube VT- third The civilian successor was produced as 215A in 1919 by Western Electric. General Smuts took van der Bijl in 1920 as a technical consultant for the government back to South Africa. He was chairman of Eskom, Iscor and the Industrial Development Corporation of South Africa. From 1934 to 1948 he was chancellor of the University of Pretoria. The industrial town of Vanderbijlpark south of Johannesburg was named after him.

From van der Bijl derived the equation for triode electron tubes. In this case, the slope S, D is the penetration and Ri is the internal resistance of the triode. In Germany, this formula is known as Barkhausensche tube formula.