Georg Simon Ohm, the law that bears his name represented the true beginning of electrical circuit analysis

Georg Simon Ohm

March 16, 1789, Munich (Germany) – July 6, 1854, Munich (Germany)

He was born into a small Protestant family in Erlangen, Bavaria (at the time, part of the Holy Roman Empire) whose father was self-taught and gave his children an excellent education based on his own teachings.

At the age of 16, he began studying at the University of Erlangen, but lost interest after only three semesters. He went to Switzerland, where in 1806, he obtained a position as a teacher of mathematics in a Gottstadt school.

He continued his studies on mathematics by reading Euler, Laplace and Lacroix until 1811, when he decided to return to his hometown. There he received his doctorate in October of that same year and began working for the university. However, when he had been practicing for a year and a half, he lived in poor conditions and did not see that his future was going to improve, so he left his position as a mathematics professor at the university.

His luck did not change, and in 1813 the Bavarian government offered him a teaching position at a disreputable school in Bamberg. Three years later, after the school closed, he was sent to another school in Bamberg, which needed help teaching mathematics and physics. During all this time, Ohm showed a visible discontent with his work, since it was not the brilliant career that he had hoped for himself: he considered himself more than just a teacher.

In 1817, a great opportunity came as a teacher of mathematics and physics at the Jesuit Lyceum in Cologne, a school better than any Ohm had been able to teach in, even boasting its own well-equipped physics laboratory. Once installed there, Ohm continued his studies in mathematics, reading the works of leading French mathematicians of the time, such as Laplace, Lagrange, Legendre, Biot and Poisson, as well as those of Fourier and Fresnel, and later with experimental work in the laboratory. of physics at the college, after he published the news of Oersted's discovery of electromagnetism in 1820.

In the Lyceum they allowed him to stay away from teaching for a year in order to continue his research, which allowed him in 1825 to begin publishing the results of his experiments on current and voltage measurements, in which he highlighted the decrease in the electromagnetic force that passes through a cable as it was longer.

In 1826, he received a generous sum of money to spend a year in Berlin to work on his publications. Ohm thought that with his publications they would offer him a good position at the university before returning to Cologne, but in 1827, time was running out and he received no better offers. Feeling diminished, he decided to stay in Berlin, resigning his position in Cologne a year later.

In 1827, he published a book in which he exposed his discovery, a theory of electricity in which he established the relationship between the intensity of an electric current, its electromotive force and resistance, formulating in 1827 the law that bears his name. which establishes that I = V/R. He states that the amount of constant current through a material is directly proportional to the voltage across the material divided by the electrical resistance of the material.

The most remarkable thing about him is that he begins by teaching the basics of mathematics with the purpose that the reader understands the rest of the book. He did so because at the time even the best German physicists lacked a proper mathematical basis for understanding the work. Reason for which he did not fully convince the veterans, who did not believe that the mathematical approach to physics was the most appropriate, for which they criticized and ridiculed his work.

His great contribution was the approach of a fundamental relationship called "Ohm's Law". That same equation had been discovered 46 years earlier by Henry Cavendish, but his semi-hermit nature prevented his conclusions from being known until they were published almost 100 years later, in 1879, by James Clerk Maxwell.

He had various temporary jobs in Berlin schools until in 1833, when he accepted a position as a professor at the University of Nuremberg, however, it was not the position according to what he believed he deserved.

In 1841, his work was recognized by the Royal Society and he was awarded the Copley Medal; the following year he was incorporated as a foreign member of the Society. So did several academies, including those of Turin and Berlin, who made him an elected member. In 1845 he was already an active and formal member of the Bayerische Akademie.

Beyond his research on electricity, he was also interested in acoustics, battery polarization and light interference. So, in 1843, he announced the fundamental principle of physiological acoustics, out of his concern with how combinations of tones are heard which he said:

"By being exposed to a complex sound created by mixing various tones, individuals are able to hear each tone separately."

But his hypotheses did not have a strong enough mathematical basis, so he ended up in a dispute with the physicist August Seebeck, who discredited his theory. Finally, Ohm acknowledged his mistakes.

In 1849, Ohm accepted a position in Munich as Curator of the Physics Cabinet of the Bayerische Akademie and gave numerous lectures at the University of Munich. Three years later, he achieved the position that he had yearned for all his life, he was appointed as full professor of physics at the University of Munich.

In addition, the unit of electrical resistance, the ohm (Ω), is named in his honor and is equal to that of a conductor in which a current (I) of one ampere (1 A) is produced by a potential of one volt (1 V) across its terminals. These fundamental relationships represent the true beginning of electrical circuit analysis.

Access to the best


on Energy and Environment
Go to resources