Faraday discovered the law of electromagnetic induction , who only attended primary school for two years, was once a student and assistant of the famous British chemist David. He is a world-renowned self-taught scientist. Because he discovered the law of electromagnetic induction in electromagnetics, invented the world's first engine, etc., he is known as the "Father of Electricity" and "Father of AC Electricity". .
"The father of alternating current" Michael Faraday
After H.C. Oersted discovered the magnetic effect of current in 11820, many physicists tried to find its reverse effect and asked whether magnetism can produce electricity and whether magnetism can act on electricity. Problem, in 1822, when D.F.J. Arago and A.von Humboldt were measuring the geomagnetic intensity, they accidentally discovered that metal has a damping effect on the oscillation of a nearby magnetic needle. In 1824, Arago conducted a copper plate experiment based on this phenomenon and found that the rotating copper plate would drive the freely hanging magnetic needle above to rotate, but the rotation of the magnetic needle was not synchronized with the copper plate. A little later, electromagnetic damping and electromagnetic driving were the earliest discovered phenomena of electromagnetic induction , but because they were not directly expressed as induced current , they could not be explained at the time.
In August 1831, Faraday wound two coils on both sides of a soft iron ring. One of them was a closed loop, with a magnetic needle placed in parallel near the lower end of the wire, and the other was connected to the battery pack and connected to the switch to form a closed loop with power. The experiment found that when the switch is turned on, the magnetic needle deflects; when the switch is turned off, the magnetic needle deflects in the opposite direction, which indicates that an induced current appears in the coil without a battery pack. Faraday immediately realized that this was a non-constant transient effect. He then conducted dozens of experiments and summarized the situations that produce induced current into five categories: changing current, changing magnetic field, moving constant current, moving magnet, and conductor moving in the magnetic field, and formalized these phenomena. Named electromagnetic induction. Furthermore, Faraday discovered that the induced current generated in different metal conductor loops under the same conditions is proportional to the conductive ability of the conductor. From this, he realized that the induced current is generated by induced electromotive force that has nothing to do with the properties of the conductor, even if there is no There is no induced current in the loop, but the induced electromotive force still exists.
Electromagnetic induction phenomenon
The electromagnetic induction phenomenon first discovered by Faraday refers to the phenomenon of induced electromotive force due to changes in magnetic flux . The direction of electromagnetic induction electromotive force can be determined by Lenz's law or right-hand rule .
The formal expression of Faraday's law of electromagnetic induction is that the magnitude of the induced electromotive force generated in a conductor loop is proportional to the rate of change of the magnetic flux passing through the area enclosed by the loop.
On October 28, 1831, Faraday invented the disc generator and obtained a method for generating alternating current. It was the first generator created by man. Faraday's discovery laid the foundation for electromagnetism and was the forerunner of Maxwell.
On August 25, 1867, Michael Faraday passed away due to ineffective treatment of illness at the age of 76.
