Nikola Tesla
Who was Nikola Tesla?
Nikola Tesla, born on 10 July 1856 in Smiljan, then part of the Austrian Empire (now Croatia), was a visionary physicist, inventor and electrical engineer. He is best known for his pioneering contributions to the development of electrical engineering and his research in the field of electricity and magnetism.Table of Contents
Illustration 1: Nikola Tesla at age 35
Nikola Tesla's work laid the foundation for modern AC power supply technology, which is used worldwide today.
His inventions, such as the alternator and the Tesla transformer, revolutionised how electrical energy is generated and transmitted.
These technologies enable the efficient transmission of electricity over long distances and form the basis for today's power grid.
For buyers of magnets, Nikola Tesla's work in the field of electromagnetism
is of particular importance.
He experimented with magnetic fields
and discovered rotating magnetic fields, which are essential for the development of alternating current motors.
These motors utilise the principles of electromagnetism to generate mechanical energy and play a pivotal role in many modern devices.
Nikola Tesla was also a pioneer in wireless communication and endeavoured to realise wireless energy transmission.
Although many of his more ambitious projects, such as the famous Wardenclyffe Tower, which was intended to supply ships at sea with electrical energy from land, were ultimately unsuccessful, his research nevertheless laid the foundations for later developments in wireless technology.
His influence extends far beyond electrical engineering and continues to inspire innovators in various technical and scientific fields to this day.
Tesla, often referred to as "the man who invented the future", remains a key figure in the history of science and technology and an inspiration to anyone interested in the mysteries of electromagnetism and its applications.
Nikola Tesla was a visionary whose inventions and ideas were far ahead of their time.
His work influences not only electrical engineering, but also radio engineering, robotics and renewable energy technologies, and his legacy lives on in the many technologies he inspired.
Inventions by Nikola Tesla
Nikola Tesla left behind an impressive legacy of inventions that still have a significant influence on our modern world today. His creativity and innovation led to the development of several key technologies that are used in various fields. His most important invention is the alternating current system, which includes the alternator as well as the necessary transformers and alternating current motors. His major inventions include:Alternating current systems:
Nikola Tesla is perhaps best known for his work on alternating current (AC) systems.
These include the alternator, transformers and the alternating current motor.
These inventions formed the basis for today's power grid and electricity supply.
The efficient transmission of electricity over long distances became possible for the first time.
The Tesla coil:
One of Nikola Tesla's most remarkable inventions is the Tesla coil (see illustration 2), a high-frequency transformer capable of generating very high voltages.
Today, these coils are utilised in various fields, including radio engineering and consumer electronics.
They also impressively demonstrate the principles of wireless energy transmission.
Radio technology:
Tesla made a significant contribution to the development of wireless communication technology.
His experiments and theories paved the way for the later development of the radio.
Although Guglielmo Marconi is known for inventing the radio, it was Nikola Tesla who researched the basic principles of wireless signal transmission.
Remote-controlled boats:
Tesla experimented with wireless remote control and demonstrated it with a remote-controlled boat, which is considered one of the first examples of remote-controlled technology.
This innovation laid the foundation for modern robotics and remote control technology.
The dynamic theory of the gravitational field:
Although less well known, Tesla also developed his own theory of the gravitational field, which differed from Einstein's theory of relativity.
Nikola Tesla's views in this field remained largely speculative and were not widely recognised by the scientific community.
Concepts for renewable energy:
Tesla also thought about renewable energy sources and experimented with concepts for utilising solar and wind energy, which underlines his vision and understanding of future energy technologies.
Two particular examples: The induction motor and the Tesla transformer
The induction motor
Nikola Tesla's invention of the induction motor in the late 19th century was a particularly significant development in the history of electrical engineering. The induction motor was one of the first efficient methods of converting electrical energy into mechanical energy.The induction motor consists of a stationary part, the stator, and a rotating part, the rotor.
The stator generates a rotating magnetic field
that is fed by alternating current.
This magnetic field then induces a current in the rotor, which generates a rotating motion based on the electromagnetic induction principle.
Tesla's induction motor was particularly revolutionary because it required no brushes or direct electrical connection to the rotor, making it more reliable and lower in maintenance than previous motor types.
This was especially important for industrial applications, as the motor could run under tougher conditions and for longer periods of time.
The introduction of the induction motor contributed significantly to the acceptance of AC systems.
Its efficiency and reliability made it ideal for numerous applications, from small household appliances to large industrial machines.
The Tesla transformer
The air-coupled Tesla transformer consists of a Tesla coil as a secondary circuit, which carries a torus as capacitance (see illustration 2) and is coupled to a high-capacitance primary circuit with a spark gap. This device is known for its ability to generate very high voltages at low currents, which can lead to spectacular visual effects such as long electrical sparks (illustration 3).The basic principle of the Tesla transformer is based on resonance.
The transformer typically consists of two parts: a primary and a secondary circuit.
Each of these circuits forms an LC resonant circuit (inductance L and capacitance C).
Illustration 2, left: Schematic principle of the Tesla transformer, in which a primary coil with very few windings is coupled to a secondary coil with lots of windings and a torus as a capacitor on the coil.
(Source: Biezl, Public domain, via Wikimedia Commons) Right: Long exposure of the discharges of a Tesla transformer.
(Source: kkiks_, CC BY 4.0,
via Wikimedia Commons, unchanged)
The primary circuit
The primary circuit contains a spark gap – a device that generates a spark and thus an electrical breakdown when a certain voltage is reached. This spark gap serves as a kind of switch that periodically closes the primary circuit (for the duration of the spark) and then interrupts it again. For the brief moment of the arc-over, the primary circuit oscillates at its natural frequency (typically 50 – 500 kHz).The secondary circuit
The secondary circuit is designed so that it has a natural resonance frequency that corresponds as closely as possible to that of the primary circuit. The oscillating magnetic field of the primary circuit is transferred to the secondary circuit through the air coupling. If the frequencies of both circuits match (resonance), energy is transferred efficiently from the primary to the secondary circuit. The secondary circuit contains a Tesla coil with an enormous number of windings. At resonance, this results in extremely high voltages in the secondary circuit. These high voltages can generate electrical discharges into the surrounding air, which are visible as long, dancing sparks (illustration 2 and 3).
Illustration 3: Nikola Tesla in his laboratory, long exposure with a Tesla transformer at work.
(Source: Photographer: Dickenson V.
Alley, restored by Lošmi, Public domain
via Wikimedia Commons, unchanged)
The physical unit tesla for the magnetic flux density
The physical unit tesla (T)
is a measure of the magnetic flux density B
in electrodynamics.
It is named after Nikola Tesla in recognition of his contributions to the field of electromagnetism.
One tesla defines the strength of a magnetic field
that permeates a square metre area \(A\)
with a magnetic flux
\(Φ\)
of one weber (Wb).
Expressed formally, one tesla equals one weber per square metre (1 T = 1 Wb/m²):
\(B = Φ/A\)
The physical unit tesla
is not only of great importance in physics, but also in technical applications.
It is used to measure the strength of magnetic fields such as those found in medical magnetic resonance imaging (MRI) systems, in research particle accelerators and in many other electromagnetic devices.
One tesla is a relatively large unit; everyday-life magnetic fields, such as Earth's magnetic field, are usually measured in microtesla (µT).
For comparison: Earth's magnetic field has a strength of around 50 µT, while medical MRI devices often work with fields in the range of 1.5 to 3 T.
However, it is not easy to generate very high magnetic fields.
The magnetic field lines
can be highly compressed for a short time using imploding coils.
The record was achieved in 2018 with an imploding special construction made of a solid copper coil that delivered 1200 tesla for a few milliseconds.
(Source: D.
Nakamura, A.
Ikeda, H.
Sawabe, Y.
H.
Matsuda, and S.
Takeyama, Review of Scientific Instruments 89, 095106 (2018); https://doi.org/10.1063/1.5044557).
It is all the more impressive that large neodymium permanent magnets
(such as those available at supermagnete.ro) already have a remanence
above 1 tesla and can withstand breakaway forces of several hundred kg.
Author:
Dr Franz-Josef Schmitt
Dr Franz-Josef Schmitt is a physicist and academic director of the advanced practicum in physics at Martin Luther University Halle-Wittenberg. He worked at the Technical University from 2011-2019, heading various teaching projects and the chemistry project laboratory. His research focus is time-resolved fluorescence spectroscopy in biologically active macromolecules. He is also the Managing Director of Sensoik Technologies GmbH.
Dr Franz-Josef Schmitt
Dr Franz-Josef Schmitt is a physicist and academic director of the advanced practicum in physics at Martin Luther University Halle-Wittenberg. He worked at the Technical University from 2011-2019, heading various teaching projects and the chemistry project laboratory. His research focus is time-resolved fluorescence spectroscopy in biologically active macromolecules. He is also the Managing Director of Sensoik Technologies GmbH.
The copyright for all content in this compendium (text, photos, illustrations, etc.) remains with the author, Franz-Josef Schmitt. The exclusive rights of use for this work remain with Webcraft GmbH, Switzerland (as the operator of supermagnete.ro). Without the explicit permission of Webcraft GmbH, the contents of this compendium may neither be copied nor used for any other purpose. Suggestions to improve or praise for the quality of the work should be sent via e-mail to
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