Štefan Anián Jedlík

Born	January 11, 1800(1800-01-11) Szímő (Zemné), Komárom county, Kingdom of Hungary, Habsburg Empire
Died	December 13, 1895(1895-12-13) (aged 95) Győr, Kingdom of Hungary, Austria-Hungary

Štefan Anián Jedlík (Jedlik Ányos István, Stephanus Anianus Jedlik) was a 19th-century inventor, engineer, physicist, and Benedictine priest. He was also member of the Hungarian Academy of Sciences, and author of several books. He is considered to be the unsung father of the dynamo and electric motor.

Life

He was born in Szimő, Kingdom of Hungary, (today Zemné, Slovakia). His mother (Róza Szabó, 1778-1828), was a member of a Hungarian noble family, while the family of his father (Ferenc Jedlik, 1767-1821) – based on the surname – was probably of Slovak origin moving in 1720 from Liptó county (now Liptov) to Szímő.

Jedlik's education began at high schools in Nagyszombat (today Trnava) and Pozsony (today Bratislava). In 1817 he became a Benedictine, and from that time continued his studies at the schools of that order, where he was known by his Latin name Stephanus Anianus. He lectured at Benedictine schools up to 1839, then for 40 years at the Budapest University of Sciences department of physics-mechanics. Few guessed at that time that his activities would play an important part in bringing up a new generation of physicists. He became the dean of the Faculty of Arts in 1848, and by 1863 he was rector of the University. From 1858 he was a corresponding member of the Hungarian Academy of Sciences and from 1873 was an honorary member. After his retirement he continued working and spent his last years in complete seclusion at the priory in Győr, where he died.

Work

Electromotor ('Electromagnetic rotor')

Jedlík's electromotor, 1829.

In 1827, Jedlik started experimenting with electromagnetic rotating devices which he later called villamdelejes forgony [elektromagnetic rotor]. He was familiar with similar experiments by Oersted, Faraday, and Barlow through various journals, including Journal für Physik und Chemie (ed. Schweigger), Annalen der Physik und Chemie (eds. Poggendorff, Gilbert), Zeitschrift für Physik und Mathematik (eds. Baumgartner, Ettingshausen), Polytechnisches Journal (ed. Dingler), as well as Gehler's Physikalisches Wörterbuch. In 1828 he demonstrated the first device which contained the three main components of practical direct current motors: the stator, rotor and commutator. Unlike in other electromotors of the time, in his prototype both the stationary and the revolving parts were electromagnetic (video, video). The motor and Jedlik's operating instructions are kept at the Museum of Applied Arts in Budapest. It still works perfectly today.

Teaching

He was a prolific author. In 1845, Jedlik was the first university professor in Kingdom of Hungary who began teaching his students in Hungarian instead of Latin. His cousin Gergely Czuczor, a Hungarian linguist, asked him to create a Hungarian technical vocabulary in physics, the first of its kind, by which he became one of its founders.

Optical and wave-mechanical experiments

In the 1850s he conducted optical and wave-mechanical experiments, and at the beginning of the 1860s he constructed an excellent optical grate.

Dynamo invention

Jedlik's best known invention is the principle of dynamo self-excitation. In the prototype of the single-pole electric starter, both the stationary and the revolving parts were electromagnetic. In essence, the concept is that instead of permanent magnets, two opposed electromagnets induce the magnetic field around the rotor.

As one side of the coil passes in front of the north pole, crossing the line of force, current is induced. As the frame rotates further the current diminishes, then arriving at the front of the south pole it rises again but flows in the opposite direction. The frame is connected to a commutator, thus the current always flows in the same direction in the external circuit.

He did not speak about his prototype until 1856; it was not until 1861 that he mentioned it in writing in a list of inventory of the university. Although that document might serve as a proof of Jedlik's status as the originator, the invention of the dynamo is linked to Siemens and Wheatstone (1867) because Jedlik's invention did not rise to notice at that time.

Impulse generator

In 1863 he discovered the possibility of voltage multiplication and in 1868 demonstrated it with a "tubular voltage generator", which was successfully displayed at the Vienna World Exposition in 1873. It was an early form of the impulse generators now applied in nuclear research. The jury of the World Exhibition of 1873 in Vienna awarded his voltage multiplying condenser of cascade connection with prize "For Development". Through this condenser, Jedlik framed the principle of surge generator of cascaded connection. (The Cascade connection was an other important invention of Jedlik).

Lissajouse patterns

With Gejza Bolemann he created Lissajouse patterns (super-position of harmonic functions) with the mechanical "predecessor" of the computer plotter (long before Ben Laponsky did his first oscilons with an electronic computer).

Literature

• Gyula Radnai, "Az akadémikus Jedlik Ányos", 1995. (Hungarian)
• Jedlik's letters to his family (Hungarian)

External links

• http://jedliktarsasag.hu/
• Jedlik at Wikipedia
• Jedlik at Slovak Wikipedia
• Jedlik at Hungarian Wikipedia