IEEE Circuits and Systems Magazine - Q3 2023 - 68

Pioneers
Gustav Robert Kirchhoff
I
n the 19th century, new electrical, magnetic, and
thermal phenomena were observed, eventually leading
to the development of electromagnetic theory
and thermodynamics as new theories of physics. These
theories were mainly developed by physicists in France,
Great Britain, and Germany. Gustav Robert Kirchhoff
was one of the German physicists
involved in this process and thus
became one of the founders of
mathematical physics, at least in
Germany. Together with Robert
Wilhelm Bunsen, he developed optical
spectroscopy and examined
the spectrum of the sun, becoming
one of the founders of astrophysics.
Kirchhoff introduced the black
body and discovered the law of
thermal radiation. However, electrical
engineers know Kirchhoff because
of his fundamental contributions
to electrical circuits and the
well-known Kirchhoff's laws.
Gustav Robert Kirchhoff was
born on March 12, 1824, in Königsberg
(now
Kaliningrad, Russia)
as the son of Friedrich Kirchhoff,
a lawyer, and Johanna Henriette
Wittke [2]. After he left the Kneiphöfische Gymnasium
at age 18, Kirchhoff studied mathematics and physics at
the Albertus University of Königsberg. Under the scientific
direction of Franz Ernst Neumann, he worked since
1843 in the mathematical-physical seminar, which was
founded by Carl Gustav Jacob Jacobi. In 1847, Kirchhoff
was honored for solving a philosophical faculty prize
task, using the revised manuscript as a dissertation. In
the same year he moved to the Friedrich-Wilhelms-Universität
Berlin, where he received his habilitation (venia
legendi) and became a private lecturer (Privatdozent).
In 1850, at the age of 25, Kirchhoff transferred to the University
of Breslau (now Wrocław, Poland), but as early
as 1854 he followed his friend Robert Wilhelm Bunsen
Digital Object Identifier 10.1109/MCAS.2023.3302392
Date of current version: 11 October 2023
68
IEEE CIRCUITS AND SYSTEMS MAGAZINE
to the University of Heidelberg, where he spent his most
fruitful years from an academic point of view. In 1857,
Kirchhoff married Clara Richelot, the daughter of his
Former Mathematics Professor F. J. Richelot. Finally, in
1875, Kirchhoff received an exceptional and honorable
vocation to the Prussian Academy of Sciences and at the
same time to the University of Berlin.
Kirchhoff died in Berlin in 1887
at the age of 63 [15].
It is not the place to present all
Gustav Robert Kirchhoff (1824-1887)
contributions to theoretical and
applied physics, we only discuss
his pioneering scientific work in
electromagnetics, which remained
a research area until the end of his
life. As early as 1845, while still a
student at the Neumann Seminar,
Kirchhoff [6] published his first scientific
paper " On electrical conduction
in a thin plate and in particular
in a circular plate " in the famous
Poggendorff's Annalen of Physics
and Chemistry. A very general formulation
of the two Kirchhoff laws
for linear DC networks is included
in the appendix of this paper but
already in the introduction of this
paper he pointed out that " The type of distribution can
be determined theoretically according to the principles
established by Ohm. " Actually, the physical laws for DC
networks were developed by Ohm [10] and formulated
verbally in his seminal original book. Kirchhoff's first
work also shows that he was interested in the development
or further development of physical measuring
devices. It is interesting that Kirchhoff formulated his
famous laws in order to analyze a resistance measuring
bridge which was a modified version of Wheatstone's
bridge published in 1843 [3]. The fundamental importance
of Kirchhoff's laws was first discovered by Poggendorff
[11], which greatly simplified or made possible the analysis
of networks with nodes connected by more than
two branches. Poggendorff [11] mentioned that he and
Wilhelm Weber had serious problems analyzing the
Wheatstone bridge. Kirchhoff [8], [9] presented the realization
of a resistance measurement bridge that put
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