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Feature article
ELECTRONICS
Inventors and their Inventions
Note that many people independently invented the same thing; those who
get the most credit were not necessarily the original discoverers. Also, many
inventions represent the culmination of
the work of many people. Some inventions are not necessarily the result of
the labours of any specific individual
but result from many contributions.
We have tried to be as comprehensive as possible, but there will be inventions or inventors we have not been
able to include in the available space.
This series contains six parts. This
first part, and the following three
that will be coming over the next few
months, will detail various individual
inventors, usually with multiple inventions over a range of dates, organised by their birth dates. The last two
parts will mostly cover inventions attributed to companies or other organisations, such as universities.
We have endeavoured to use multiple sources to find accurate dates;
dates often vary between sources,
sometimes significantly.
Here is our list of inventors by date
of birth (up to 1804):
Thales of Miletus
static electricity
Who laid the groundwork for modern technology?
Modern inventions like transistors, ICs and wireless
communications didn’t come out of thin air; thousands
of brilliant scientists and inventors had to discover
every aspect of the electronic technology that made
them possible over the last few hundred years.
Part 1: by Dr David Maddison
W
e tend to think of electronics
as a relatively recent development. Transistors, ICs and
many other keystone technologies of
the current age were created from the
late 1960s to the early 2000s. However,
many important discoveries had to be
made before any of that was possible.
Modern devices like computer CPUs
rely on principles that were discovered
hundreds of years ago. We will look at
the people behind those discoveries
in this series of articles. The inventors
and inventions described herein form
the basis of all modern electronics.
You may be surprised at how early
some advanced concepts were conceived. Many modern devices were in26
https://unsplash.com/photos/_kdTyfnUFAc
vented way ahead of their time. They
often failed to find a use then, only to
become very popular later.
Many of the scientists and engineers
described below contributed far more
than we can describe in the space available. It was common to be a polymath
(multi-disciplined) ‘back in the day’.
We will focus on those areas of discovery and invention most relevant to
electricity and electronics.
c.624BCE-c.546BCE
Described the generation of static
electricity by rubbing amber, which
caused it to attract feathers and other
light materials. He also observed that
lodestone, a form of magnetite naturally magnetised by lightning, could
attract iron.
Theophrastus
pyroelectricity
c.371BCE-c.287BCE
Is said to have discovered pyroelectricity, the property of a material
to temporarily become charged when
heated and attract light materials like
ash, similar to when amber is rubbed.
William Gilbert
electricity
1544-1603
Coined the term “electricus”, from
which the word electricity is derived.
He also explained that compasses
worked because the Earth is a giant
magnet with an iron core. He wrote a
book in 1600 with the title “De Magnete”. You can read that book at www.
gutenberg.org/ebooks/33810
He also invented the instrument
Recent articles in Silicon Chip magazine on electronics tech.
All About Batteries, January–March 2022; siliconchip.au/Series/375
The History of Transistors, March–May 2022; siliconchip.au/Series/378
IC Fabrication, June & July 2022; siliconchip.au/Series/382
Display Technologies, September & October 2022; siliconchip.au/Series/387
Computer Memory, January & February 2023; siliconchip.au/Series/393
Practical Electronics | January | 2025
The History of Electronics, part one
Fig.1: Ebenezer Kinnersley’s
‘Electrical FIRE’ lecture
notice. Source: Brown
University Library (https://
library.brown.edu/dps/
curio/2013/05/).
now known as the electroscope, which
detects the presence of electric charge.
Gilbert mistakenly did not believe
electricity and magnetism were related; Hans Christian Ørsted and
James Clerk Maxwell later showed
them to be.
Otto von Guericke
electrostatic generator
1602-1686
He invented the first electrostatic
generator, a sulfur sphere that could
be rubbed to impart an electric charge
to attract or repel objects. It inspired
other, more advanced frictional generators.
Christiaan Huygens
wave theory of light
1629-1695
Developed the wave theory of light
in 1690, which related to electric and
magnetic fields.
Francis Hauksbee the Elder
modified electrostatic generator
1660-1713
Made a modified version of Otto
von Guericke’s electrostatic generator in 1705, a partially evacuated glass
sphere into which mercury was introduced. If rubbed to generate a charge,
a glow was produced where the glass
was touched.
This led to the much later development of the gas discharge lamp, neon
lighting and mercury vapour lamps. You
can read his book “Physico-mechanical
experiments” at https://catalogue.nla.
gov.au/catalog/3171279
Johann George Schmidt
pyroelectricity
unknown
Observed in 1707 that the mineral
tourmaline had a property we now
know as pyroelectricity.
Stephen Gray
electrical conductivity
1666-1736
Discovered the principles of electrical conductivity and distinguished
between conductors and insulators.
He also made discoveries in electrical induction, imparting a charge into
another object without contact. He
received little credit for his discoverChristiaan
Huygens also
invented the
pendulum
clock.
Source:
https://w.
wiki/7ATc
Practical Electronics | January | 2025
Fig.2: Kinnersley’s “electric
air thermometer” used a
spark discharge to push
water up a tube. Source:
https://w.wiki/78sQ
ies, but today, some know him as the
“father of electricity”.
Pieter van Musschenbroek
Leyden jar / capacitor
1692-1761
Along with his student and a collaborator, he invented what became
known as the Leyden jar in 1756, the
original capacitor. It was used to store
electrical energy produced by frictional generators. It consisted of a glass jar
filled with water, a brass rod and another conductor.
You can easily make a Leyden jar;
see the video from ElectroBOOM
at https://youtu.be/xjW-isgOijs and
www.wikihow.com/Make-a-Leyden-Jar
Ewald Georg von Kleist
Kleistian jar
1700-1748
Invented the Kleistian jar in 1745,
a form of Leyden jar.
Benjamin Franklin
lightning rods, glass harmonica etc
1706-1790
He named positive and negative
charges in 1747. In 1748, he constructed a multi-plate capacitor with glass
and lead plates. In that same year, he
invented the “electric wheel”, a type
of electrostatic motor that would run
at 12-15RPM from a charge supplied
by Leyden jars.
In 1750, he showed that Leyden jars
discharged more easily near a pointed
rod, leading to the invention of lightning rods (also see Kinnersley’s entry).
In 1752, he flew a kite in a thunderstorm to charge a Leyden jar attached
to the wet string, proving that lightning was electricity. (The following
two people who tried that were electrocuted.)
In 1751, he published a series of
pamphlets on electricity (pemag.au/
link/abnr).
Carl Linnaeus
pyroelectricity
1707-1778
Determined that pyroelectricity was
a type of electricity in 1747. He later
became known as Carl von Linné after
being ennobled
Ebenezer Kinnersley
electric fire / electricity
1711-1778
Performed experiments with “electric fire”, as electricity was then called
– see Fig.1.
Benjamin Franklin described him
as “an ingenious neighbor”. In 1748,
he discovered that electricity passed
through water. In 1751-2, he held a
series of lectures about electric fire.
In his March 1752 lecture, he suggested the lightning rod to protect
structures from lightning before
27
Feature article
Benjamin
Franklin was
one of the
Founding
Fathers of
the USA.
Source:
https://w.
wiki/7ATw
Benjamin Franklin in 1748. It was incapable of useful work, but some call
it the first electric motor.
It consisted of a free-spinning star
with angled, pointed ends that were
charged from a power source. Ionised gas from the tips caused it to
rotate. For more details, see pemag.au/
link/abn2
Franz Aepinus
electricity and magnetism
1724-1802
He was the first to publish a treatise
on electricity and magnetism (see his
book at: pemag.au/link/abnu).
Johan Carl Wilcke
electrophorus
Franklin did his kite experiment. In
1761, he wrote a letter to Franklin
and, in 1763, published details of an
“electric air thermometer” – see Fig.2.
He demonstrated that electricity could produce heat. In 1761, he
used electricity from Leyden jars to
heat metals to incandescence, producing visible light, paving the way
for the light globe. See “Expt. 11” in
his letter to Franklin (pemag.au/link/
abp2).
You can find instructions to make
a “proof of concept” light globe on
Hackaday: pemag.au/link/abnk
1732-1796
Invented the electrophorus, a device
to produce static electricity, in 1762.
Luigi Galvani
bio-electricity
1737-1798
He is famous for discovering that
frog’s legs will twitch with the application of an electric discharge from a
charged Leyden jar. He also made the
legs move with two differing metals
that generated a current like a battery.
Due to this early work in the field of
bioelectricity, many modern electrical-
related phenomena are named after
Galvani.
Alessandro Volta
battery (voltaic pile)
1745-1827
He improved the electrophorus in
1775. Then in 1800, he invented what
is now known as the voltaic pile or battery made of copper and zinc, using
either saltwater or sulfuric acid electrolyte. He acknowledged the contributions of William Nicholson, Tiberius Cavallo and Abraham Bennet to
his battery work.
The unit of electrical potential, the
volt (V), was named in his honour. He
discovered by accident that a short circuit of his voltaic pile caused a copper
wire to glow, confirming the principle
of the incandescent light globe.
Pierre-Simon Laplace
Laplace transform
1749-1827
Developed the Laplace transform
in 1785. It is used to solve differential equations, making it essential for
circuit analysis.
1737-1806
Vasily Vladimirovich Petrov 1761-1834
Invented the “electrical whirl”
(Fig.3), described in 1745 (pemag.
au/link/abnt). It was an electrostatic
reaction motor, also demonstrated by
Invented the torsion balance, which
enabled him to measure forces of attraction or repulsion between charged
or magnetised bodies. Coulomb’s law
states that the force between two electrically charged bodies is proportional
Discovered the electric arc in 1802
after he built the world’s largest voltaic pile, comprising 4200 copper and
zinc discs. In 1803, he proposed several uses for the electric arc, such as
lighting, welding, metal processing etc.
Fig.3: an electric whirl similar to the
one invented by Andrew Gordon in
1745. This one is on display in the
physics department of Washington
and Lee University. Source: http://
physics.kenyon.edu/EarlyApparatus/
Static_Electricity/Electric_Whirl/
Electric_Whirl.html
Fig.4: Wollaston’s improved battery with removable electrodes.
Source: https://w.wiki/78sR
Andrew Gordon
electrostatic reaction motor
28
1712-1751
Charles Coulomb
to the magnitude of their electric charge
and the inverse square of the distance
between them.
This was known earlier, but it is
named after Coulomb, as he was the
first to publish it in 1785. The Coulomb
(C) is also the unit of electric charge.
Coulomb’s law / electric charge
electric arc – welding
Practical Electronics | January | 2025
The History of Electronics, part one
William Hyde Wollaston
1766-1828
static electricity and electromagnetic induction
Fig.5: an 1878 reproduction of one of Davy’s
original arch lamps by Augustin Privat Deschanel.
Source: https://w.wiki/78sS
Demonstrated that static electricity was the same as from voltaic piles
in 1801. He was said to have “accidentally” discovered electromagnetic induction 10 years before Faraday
(who made the discovery in 1831)
and made a failed attempt to build
an electric motor.
He built an improved type of copper/
zinc battery in which the electrodes
were raised from the electrolyte when
not in use, improving the life – see
Fig.4.
John Dalton
atomic theory – materials
1766-1844
Contributed to atomic theory in
ways that improved the understanding of conductors, insulators and semiconductors.
Thomas Johann Seebeck
thermocouples / thermopiles
1770-1831
Discovered in 1822 that a junction
of two dissimilar metals produced a
current. This is the basis of thermocouples, used to measure temperature, and thermopiles, which convert
heat into electricity (such as radioisotope thermoelectric generators on
spacecraft).
Thomas Young
expanded on wave theory
1773-1829
He expanded on the wave theory
of light (first described by Huygens),
vision and colour theory.
André-Marie Ampère
Amperè’s force law and solenoid
1775-1836
Set out to discover the relationship
between electricity and magnetism.
In 1820, Ampère’s friend, Dominique
François Jean Arago, demonstrated the
discovery of Hans Christian Ørsted
that a current-carrying wire deflects a
magnetised needle.
Ampère determined that two parallel current-carrying wires would either
attract or repel each other depending
on the relative current directions and
established Ampère’s force law. He invented the solenoid and had an idea
for an electric telegraph. The SI unit
for electric current, the amp (A), is
named after him. Inspired by Ørsted,
he also established Ampère’s righthand grip rule.
Carl Friedrich Gauss
ionosphere and electric telegraph
1777-1855
Popularised Gauss’ law in 1813, although it had already been discovered
by Joseph Louis Lagrange in 1762.
In 1839, he postulated that an electrically conducting region of the atmosphere, now known as the ionoPractical Electronics | January | 2025
sphere, reflected radio waves. The unit
of magnetic induction, the gauss (G), is
named after him. He had achievements
in many other areas. He worked with
Wilhelm Eduard Weber to develop an
electric telegraph in 1833.
Hans Christian Ørsted
1777-1851
Oersted’s law and right-hand thumb rule
Discovered in 1820 that the needle of
a compass would deflect near a current-
carrying wire, establishing that an electric current had a magnetic field, the
first connection between electricity and
magnetism. He established Oersted’s
(or Ørsted’s) law which states that an
electric current establishes a magnetic
field around it.
That led to the “right-hand thumb
rule”, which describes the relationship between a current and its magnetic field. A unit of magnetic field
strength, the oersted (Oe), is named
after him.
Sir Humphry Davy 1st Baronet
carbon arch lamp
1778-1829
Invented the carbon arch lamp, later
renamed from arch to arc (see Fig.5),
in 1802, 1805, 1807 or 1809 (depending on the source). He used charcoal
sticks and a 2000-cell battery to strike
an arc across a 100mm gap. The electrodes were originally horizontal, and
the arc was shaped like an arch, hence
the name.
Arc lamps were widely used for
street and commercial lighting from
the 1870s until they were replaced
by incandescent lighting from the
early 1900s (except for specific applications like searchlights and movie
projectors).
Movie reels used to commonly be
2000ft (610m) long, with a runtime of
about 22 minutes. That coincided with
the life of carbon rods in pre-1970s
theatre projectors. The projectionist
would change the carbon rods at the
same time as the reel.
In 1801 or 1802, Davy also connected
a piece of platinum across a 2000-cell
battery, which caused it to glow, the
basis for later experiments in incandescent lighting.
Michael Faraday was Davy’s assistant from 1813 to about 1815, and occasionally helped him after that, such
as with the Miner’s Safety Lamp.
William Sturgeon
electromagnet
1783-1850
Invented the electromagnet in 1824
– see Fig.6. It comprised 18 turns of
copper wire on a lacquered iron Ushaped core, 30cm long and with a
13mm diameter. It was powered by
a copper-zinc-acid battery. The cups
contain mercury to make electrical
connections. The magnet could support 4kg.
Samuel Hunter Christie
1784-1865
“diamond method” (Wheatstone Bridge)
Published the “diamond method” to
compare resistances in 1833, a forerunner of the Wheatstone Bridge.
Baron Pavel Schilling
Schilling telegraph
1786-1837
Made numerous contributions to
telegraphy and other areas. One of
those inventions was the Schilling
Fig.6: William
Sturgeon’s
electromagnet.
Source: https://
w.wiki/78sT
29
Feature article
telegraph, a type of ‘needle telegraph’
that sent a code along a series of wires
to indicate the letter according to a
binary code.
His first telegraph was shown in
1828. It used only two wires with an
innovative variable-length binary code
to encode 40 letters. The current direction also varied, so two wires could
give eight different states. He demonstrated another instrument with six
wires in 1832.
To transmit 40 different characters,
six wires were needed for signalling,
one for calling and one for a return.
He abandoned the project because,
from 1825, Czar Nicholas I of Russia
opposed any form of mass communication and prohibited the public discussion of telegraphy.
V² V
ΩA² Ω Ω
VA
ΩW
W
A
W
V
W A
V Ω
V²
W W
ΩA A²
W
Ω
V
A
Fig.7: an Ohm’s Law wheel calculator.
Source: https://w.wiki/78sV (CCSA-3.0).
Conducted experiments with magnetism, mostly in 1823-1826. In 1824,
he observed “rotary currents” or eddy
currents. “Arago’s rotations” demonstrated interactions between a spinning non-magnetic conductor such as
a copper disc and a magnetised body
like a compass needle or magnet.
In it, he detailed his theory of electricity, including the concept of resistance and what is now known as
Ohm’s law – see Fig.7. In 1825, he
used different lengths of wire (10cm,
41cm, 183cm, 315cm and 762cm) to
produce different resistances, deriving Ohm’s law. It might be argued
that he invented the resistor, although
the concept of resistance was already
known at the time. The unit ohm (Ω)
is named after him.
Sir Francis Ronalds
Michael Faraday
Dominique François Jean Arago 1786-1853
eddy currents
electric telegraph
1788-1873
Produced the first working electric
telegraph in 1816. It was not until two
decades later that commercialisation
happened.
electromagnetic induction
1791-1867
Published “The Galvanic Circuit Investigated Mathematically” in 1827 –
see pemag.au/link/abp3
Built a device to produce continuous “electromagnetic rotation”, now
called the homopolar motor (Figs.8 &
9) in 1821, soon after Ørsted discovered electromagnetism.
Faraday had discussed such a device
with Sir Humphry Davy and William
Hyde Wollaston, but failed to acknowledge them as contributing to his inven-
Michael Faraday holding what is most
likely ferromagnetic material. Source:
https://w.wiki/7AUi
Fig.8: two versions of a magnetic
rotation apparatus, the first motor.
On the left, the lower magnetic rod
rotates about the centre, while on the
right, the upper wire rotates about the
centre magnet. The liquid is mercury.
Source: Michael Faraday.
Georg Simon Ohm
Ohm’s law
30
1789-1854
tion, causing controversy. See: pemag.
au/link/abn4
In 1831, Faraday discovered electromagnetic induction, demonstrating that a change in the magnetic
field within a circuit induces an electromotive force (EMF) – see Fig.10.
This discovery is the basis for electric power generation and led to the
invention of the electrical generator
and transformer. Joseph Henry independently discovered it in 1832, but
Faraday published it first.
In 1833, he published “Faraday’s
laws of electrolysis”, introducing terms
such as electrode, anode, cathode, electrolyte and ion. He observed that the
resistance of silver sulfide decreased
as its temperature increased, the first
mention of what we now call a thermistor, a semiconductor with a strongly temperature-dependent resistance.
This was also the first observation of
a semiconductor.
The unit of capacitance, the farad
(F), is named after him. Faraday also
made numerous contributions in other
areas; his theoretical work on the
nature of the electromagnetic field
led to the development of field theory
in physics.
Samuel Morse
Morse Code
1791-1872
Developed the concept of the single-
wire telegraph and invented Morse
Code in 1840 (later enhanced by Alfred
Lewis Vail). In developing the telegraph, Morse had a problem of limited
range, which he solved with the help
of Professor Leonard Gale, by adding
relay circuits.
Fig.9: a simple homopolar motor you
can make with a battery, a length
of wire, a neodymium magnet and
a steel screw. Source: https://w.
wiki/78sX (CC-BY-SA-2.5).
Practical Electronics | January | 2025
The History of Electronics, part one
+
−
Fig.10: an iron ring apparatus used by Faraday to observe electromagnetic
induction. Momentarily completing the circuit on the left resulted in a
momentary current on the right. Source: https://w.wiki/78sW
Morse was contracted to build a
61km telegraph line between Washington, DC and Baltimore in 1843,
which opened in 1844, with the first
words transmitted being “What hath
God wrought”. By 1850, 19,300km
of telegraph lines had been laid
across the USA. Morse’s 1840 telegraph patent can be seen at pemag.au/
link/abn6
The Morse Code standard today (still
in use by some radio hams) is defined
by ITU-R M.1677-1 and is based upon
the work of Friedrich Gerke in 1848,
which led to the International Morse
Code of 1865.
The hydrogen and oxygen produced
were used in a form of stage lighting
called limelight. The generator was
also used for electric arc lighting and
galvanising. The AC generated by the
machine was converted to DC by a
commutator.
Johann Poggendorff
slide wire potentiometer
1796-1877
Invented the slide wire potentiometer (variable resistor) in 1841. Around
1870, he also developed an electrostatic motor.
Joseph Henry
1799-1878
electromagnet and mutual inductance
Fig.11: Joseph Henry’s “intensity
magnet”. Source: https://w.wiki/78sY
motor based on a rocking rather than
rotary motion (see Fig.12).
The unit of inductance, the henry (H),
is named after him; it is thought that
Henry discovered inductance before
Faraday, but Faraday published his
findings first.
Patented a magneto generator in 1850
for decomposing water by electrolysis.
Improved upon Sturgeon’s electromagnet of 1824, in 1827, by using
tightly wrapped silk-insulated wire
rather than the uninsulated wire of
Sturgeon – see Fig.11. This allowed
Henry to use many layers of wire to
make a more powerful magnet. He
also discovered self-induction and
mutual inductance.
In 1831, he made the world’s first
commercial electrical product, a powerful electromagnet to separate magnetite from crushed ore (see the video at
https://youtu.be/ru-daEOuUjs). Also
in 1831, he developed the first electric
Joseph Henry in 1879. Source:
https://w.wiki/7AU$
Fig.12: Joseph Henry’s rocking beam electric motor of 1831. It pivoted in the
middle with its ends in line with permanent magnets (C and D). As it rocked,
electrodes contacted batteries at the ends (G and F), the magnet polarity
reversed, and the beam would rock the other way. Source: https://siarchives.
si.edu/collections/siris_sic_13161
Marcellin Jobard
incandescent lighting
1792-1861
Suggested incandescent lighting
in 1838, quoting É.M. Alglave and J.
Boulard, “a small strip of carbon in a
vacuum used as a conductor of a current, would emit an intense, fixed, and
durable light”. His student, CharlesFrançois de Changy, commenced work
on the idea in 1844.
Floris Nollet
magneto generator
1794-1853
Practical Electronics | January | 2025
Nicholas Joseph Callan
induction coil and Maynooth battery
1799-1864
He invented the induction coil in
1836. It is a form of transformer driven
by a pulsating direct current at about
20Hz using an “interrupter” to make
and break the current flow. Despite
not inventing it, Heinrich Daniel Ruhmkorff patented it in 1851 and then
commercialised it.
In 1848, he also commercialised the
world’s largest battery at the time, the
31
Feature article
Fig.13: the Maynooth
battery. At the back
is the zinc plate;
in front of it is a
porous ceramic pot.
Both are inside
the iron
container,
which
forms the
other plate.
Source:
Maynooth
College
Museum –
pemag.au/
link/abp7
“Maynooth battery” (Fig.13) from iron
and zinc, with 136L of acid and 577
individual cells. Back then, there was
no way to measure voltage or current,
so he measured the lifting capacity of
an electromagnet to test its relative
power.
James Bowman Lindsay
incandescent light globe
1799-1862
Invented the first incandescent light
globe in 1835, enabling him to “read
a book at the distance of 1½ foot”,
but he never patented it and did not
receive credit. In 1845, he suggested
that telegraphy could work across
water, including the Atlantic. He
proposed welding to join the cables
and sacrificial anodes for corrosion
protection.
Frederick Collier Bakewell
fax machine
1800-1869
Demonstrated an “image telegraph”
machine in 1851, an early fax machine
and an improvement upon the system
of Alexander Bain. The system worked
by drawing on metal foil using insulating ink. The foil was rolled into a cylinder, and a stylus read the conducting
and insulating areas, converting them
into signals to be transmitted.
The image was reconstructed on
treated paper that electrical impulses
could discolour. Keeping appropriate
synchronisation at both ends was difficult, and the system was never commercialised.
Moritz Hermann
Jacobi’s law
Fig.14: Jean-Daniel Colladon’s
experiment demonstrating total
internal reflection in a stream of
water. Source: La
Nature magazine,
1884.
Also known as Boris Semyonovich
(von) Jacobi, invented a process for
making printing plates by electroplating in 1838. In 1839, he made an 8.5mlong battery-powered boat that carried
14 passengers.
He studied electric motors and, in
1840, published the maximum power
theorem or Jacobi’s law, which states
that for maximum power transfer, the
load resistance must match the source
resistance. He also worked on the development of the electric telegraph
during 1842-1845.
Charles Wheatstone
telegraph and Wheatstone bridge
Fig.15: a replica
of Weber’s electrodynamometer
made in 1961.
Source: https://
americanhistory.
si.edu/collections/
search/object/
nmah_1273644
32
1801-1874
1802-1875
He performed an experiment in 1834
to determine the “velocity of electricity”. His result was about 50% too high.
In 1837, Wheatstone also began work
with William Fothergill Cooke on the
telegraph. In 1843, he improved and
popularised Samuel Hunter Christie’s
“diamond method”, which became
known as the Wheatstone Bridge.
Jean-Daniel Colladon
total internal reflection (TIR)
1802-1893
Demonstrated total internal reflection in a falling stream of water in
1842 (an experiment which can be
done at home) – see Fig.14. This allowed optical fibres to be developed
much later. The original idea was used
to illuminate water fountains such as
at the Paris World Exposition of 1889.
Frederick de Moleyns
1804-1854
platinum filament incandescent light globe
He obtained the first patent for an incandescent light globe in 1841. It used
a platinum filament, although he also
experimented with carbon filaments.
Emil Lenz
1804-1865
Lenz’s law, resistive heating and electroplating
Formulated Lenz’s law in 1834,
which specifies the direction of a current induced by a magnetic field. He
also independently discovered Joule’s
law (or the Joules-Lenz law) in 1842,
which describes how an electric current
causes a conductor to heat, otherwise
known as resistive or ohmic heating.
He also participated in the development of electroplating with his friend
Moritz Hermann.
Louis Breguet
Foy-Breguet telegraph
1804-1883
Developed a needle telegraph in 1842,
the Foy-Breguet telegraph, used on the
French railways and in Japan. In 1847,
he suggested using finer diameter wires
to protect telegraph wires against lightning strikes, the predecessor of the fuse.
Wilhelm Eduard Weber
electrodynamometer
1804-1891
Together with Carl Gauss, he built the
first working electric telegraph, nearly
1.6km long, in 1831. Weber developed
many sensitive devices for detecting
and measuring electric currents and
magnetic fields, including precise measurements of the Earth’s magnetic field.
He also invented the electrodynamometer (Fig.15), a device that can
measure current, voltage or power
via the interaction of magnetic fields
through two coils. This device was
used to validate Ampère’s force law
experimentally. The SI unit of magnetic flux, the weber (Wb), is named
after him. For more on Weber, visit:
pemag.au/link/abn7
Next month
That’s all we have room for this
month. The second article in this
series, to be published next month,
will continue the chronological list
PE
of early inventors.
Practical Electronics | January | 2025
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