Malcolm Davidson

Malcolm Davidson
Known for	Ivor Catt
Scientific career
Fields	Electromagnetic theory, digital electronics

Malcolm Davidson is a researcher in electromagnetic theory and digital electronic design, known chiefly as a long-time collaborator of the British electronics engineer Ivor Catt. Together with Catt and David S. Walton he formed the "Catt, Davidson and Walton" partnership whose late-1970s papers and books challenged the conventional textbook treatment of Maxwell's displacement current.

Biography

Little biographical information about Davidson has been published. He became associated with Ivor Catt and Dr. David S. Walton during the 1970s, when the three worked jointly on the theory and practice of high-speed digital logic and on the electromagnetic behaviour of capacitors and transmission lines. As part of this research Davidson interviewed H. J. Josephs, one of the recognised authorities on the work of Oliver Heaviside, whose concept of "energy current" underlies the group's approach to electromagnetism.

Scientific contributions

Davidson's principal contribution lies in the group's re-examination of the capacitor. Walton had proposed that a capacitor is properly understood as a transmission line; Davidson argued that on this view the exponential RC charging waveform must be built up from a series of small discrete steps, a result which supported the transmission-line model of the capacitor. This line of reasoning led, in May 1976, to the group's conclusion that the concept of displacement current is unnecessary — a step central to what Catt later called "Theory C".

The resulting arguments were set out in two articles in Wireless World: "Displacement current" (December 1978) and "The History of Displacement Current" (March 1979), both co-authored by Catt, Davidson and Walton. The articles provoked considerable controversy among electrical engineers and physicists.

In parallel, Davidson co-authored with Catt and Walton the textbooks Digital Hardware Design (Macmillan, 1979) and Digital Electronic Design, which presented practical design rules for fast digital systems based on the transmission-line view of interconnect and power distribution.

Publications

• Ivor Catt, David S. Walton and Malcolm Davidson, Digital Hardware Design, Macmillan, 1979. ISBN 0-333-25981-5
• Ivor Catt, David S. Walton and Malcolm Davidson, Digital Electronic Design, Volume 1, CAM Publishing, 1979. ISBN 0-906340-00-4
• Ivor Catt, Malcolm Davidson and David S. Walton, "Displacement current", Wireless World, December 1978
• Ivor Catt, Malcolm Davidson and David S. Walton, "The History of Displacement Current", Wireless World, March 1979

External links

• Ivor Catt (Wikipedia)
• Ivor Catt's website