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ELECTRONICS Inventors and their Inventions 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 three parts. This first part, and the follow-up next month, will detail various individual inventors, usually with multiple inventions over a range of dates, organised by their birth dates. The third and final part will mostly cover inventions attributed to a company or other organisation, such as a university. 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 1847): 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 O ver the last few years, we have examined many aspects of modern electronics history, such as transistors, batteries, IC fabrication, display technologies and computer memory (see the panel below). However, those articles don’t tell the full story because of how many important discoveries had to be made before any of that was possible. 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, as we were, at how early some advanced concepts were conceived. Many modern devices were invented way ahead of their time. 12 Silicon Chip https://unsplash.com/photos/_kdTyfnUFAc 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. Note that many people independently 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 lighting, 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 1544-1603 electricity 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 Other recent articles on the development of electronics 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 Australia's electronics magazine siliconchip.com.au 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-­ discoveries, but today, some know him mechanical experiments” at https:// as the “father of electricity”. catalogue.nla.gov.au/catalog/3171279 Pieter van Musschenbroek 1692-1761 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 Christiaan Huygens also invented the pendulum clock. Source: https://w. wiki/7ATc siliconchip.com.au Leyden jar / capacitor 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 harmonic 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 Australia's electronics magazine Fig.2: Kinnersley’s “electric air thermometer” used a spark discharge to push water up a tube. Source: https://w.wiki/78sQ 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 (siliconchip. au/link/abnr). Carl Linnaeus 1707-1778 pyroelectricity 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 October 2023  13 Benjamin Franklin was one of the Founding Fathers of the USA. Source: https://w. wiki/7ATw by 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 siliconchip.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: siliconchip.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 (siliconchip.au/link/ abp2). You can find instructions to make a “proof of concept” light globe on Hackaday: siliconchip.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. Charles Coulomb Coulomb’s law / electric charge 1737-1806 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. Alessandro Volta 1745-1827 battery (voltaic pile) 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 Developed the Laplace transform in 1785. It is used to solve differential equations, making it essential for circuit analysis. Vasily Vladimirovich Petrov electric arc – welding Invented the “electrical whirl” (Fig.3), described in 1745 (siliconchip. au/link/abnt). It was an electrostatic reaction motor, also demonstrated 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 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 14 Silicon Chip 1712-1751 Australia's electronics magazine 1749-1827 1761-1834 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. siliconchip.com.au Fig.5: an 1878 reproduction of one of Davy’s original arch lamps by Augustin Privat Deschanel. Source: https://w.wiki/78sS William Hyde Wollaston 1766-1828 static electricity and electromagnetic induction 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 ionosphere, siliconchip.com.au 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 Australia's electronics magazine 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 U-shaped 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 October 2023  15 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. Dominique Fançois Jean Arago 1786-1853 eddy currents 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. Sir Francis Ronalds electric telegraph 1788-1873 Produced the first working electric telegraph in 1816. It was not until two decades later that commercialisation happened. 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). 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. Michael Faraday electromagnetic induction 1791-1867 Published “The Galvanic Circuit Investigated Mathematically” in 1827 – see siliconchip.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 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 16 Silicon Chip 1789-1854 Australia's electronics magazine to his invention, causing controversy. See: siliconchip.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). siliconchip.com.au + − 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 siliconchip.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. electrolysis. 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 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 siliconchip.com.au 1794-1853 Australia's electronics magazine Nicholas Joseph Callan induction coil and Maynooth battery 1799-1864 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 1951 and then commercialised it. In 1848, he also commercialised the world’s largest battery at the time, the October 2023  17 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 – siliconchip. 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 8.5m-long 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 18 Silicon Chip 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. Australia's electronics magazine 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 1804-1883 Foy-Breguet telegraph 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: siliconchip.au/link/abn7 Robert Davidson electric train 1804-1894 Built the first electric locomotive in 1837, which was powered by galvanic siliconchip.com.au cells. He then built a full-sized train in 1842 called “Galvani”; it was around 5m long. Edward Davy electric relay 1806-1885 He worked on the electric telegraph during 1835-1838 and was considered a contributor equal to Cooke and Wheatstone by J.J. Fahie. In 1837, he invented the electric relay, or “electric renewer” as he called it, as part of his telegraph system. In 1838, he migrated to Australia. Duchenne de Boulogne electrophysiology 1806-1875 Experimented with electrical stimulation on parts of the human body and is considered a pioneer in electrophysiology. He first published his work, “De l’electrisation localisée...” in 1855. You can read that book in the original French at siliconchip.au/link/abn8 Alfred Lewis Vail improved on Morse Code 1807-1859 Was involved with Samuel Morse in commercialising telegraphy 18371844. He enhanced Morse Code by simplifying the alphabetic system, making it easier to decode, along with other physical improvements. Antonio Meucci telephony and dynamic microphone 1808-1889 According to some, he was the inventor of telephony. His notes show he produced a device in 1856 that The invention of electric light The story of the invention of electric light is far too long and complicated to fully cover here. We have included highlights, but if you want to know more, read “The Invention of the Electric Light” (236 pages) by B.J.G. van der Kooij, a free PDF download from siliconchip.au/link/abnh communicated voice via wires from his basement laboratory to his wife upstairs in their New York home. This included a type of dynamic microphone with a wire coil moving in response to sound within a magnetic field. From 1856 to 1870, he developed more than 30 types of phone apparatus. In 1860, he publicly demonstrated his “teletrofono” in New York. In 1870, he transmitted voice signals over more than 1.6km of wire. In 1871, he submitted a patent caveat to the US Patent Office. This document was essentially a notice of an intent to file a patent, but Meucci didn’t have the money to submit a patent application. Had he been able to, it might have stopped Alexander Graham Bell from receiving his telephone patent in 1876. Hippolyte Pixii 1808-1835 hand-cranked dynamo (electrical generator) Invented a hand-cranked dynamo in 1832 based on Michael Faraday’s discovery of electromagnetic induction. It produced an alternating current when a horseshoe (permanent) Fig.16: Pixii’s dynamo. This later version produces pulsating direct current using the commutator below the magnet. Source: https://w. wiki/78sZ siliconchip.com.au magnet passed over two iron cores – see Fig.16. At the time, DC was the preferred means of current for experiments. Upon André-Marie Ampère’s suggestion, a commutator to reverse the current direction every half turn was later added to produce pulsating direct current. William George Armstrong hydroelectric power station 1810-1900 He built the first hydroelectric power station (Fig.17) in 1870. It was the Burnfoot Power House at Cragside Estate, Rothbury, England and used a Siemens dynamo. He was titled 1st Baron Armstrong. Alexander Bain electric clock and facsimile machine 1810-1877 Patented an electric clock in 1841 with John Barwise. Its pendulum was driven by electromagnetic pulses. It included a reference to an “earth battery” made of dissimilar metals, buried in the ground, as a power source. He also patented a telegraph in 1843 that printed messages, an early form of the facsimile machine. The image to be Fig.17: the first hydroelectric power station, on a private estate in Rothbury, England. Source: https://w.wiki/78sa (CC-BY-SA-4.0). Australia's electronics magazine October 2023  19 Controversy over the invention of the telephone You may have noticed many references to various people who made telephone-­ related inventions. The matter of who invented the telephone has been subject to considerable controversy, including the long-running court case in the USA from 1878 to 1901 involving A.G. Bell, Thomas Alva Edison, Elisha Gray, Emil Berliner, Amos Dolbear, J. W. McDonagh, G. B. Richmond, W. L. Voelker, J. H. Irwin and Francis Blake Jr. Bell and the Bell Telephone Company eventually won that case, along with 600 other cases involving the invention of the telephone that went to trial. Another controversy involved Antonio Meucci. See https://w.wiki/78sh transmitted had to be formed by metal pins arranged on a rotating cylinder, so it was not very practical. In 1846, he patented a printing telegraph that printed Morse Code on moving paper tape using chemical rather than mechanical means. He also devised a punched paper tape system for prerecorded messages that could be transmitted quickly. It could send 325 words per minute, compared to the Morse system at only 40 words per minute. Samuel Morse claimed patent infringement, and the system was not widely used. Frederick Hale Holmes 1812-1875 continuous current electro generators Developed generators to power electric arc lighting in 1853. In 1856, he patented a magneto to power lighthouse arc lamps – see Fig.18. Heinrich Geißler 1814-1879 Geissler tube – early form of neon lighting Invented the Geissler tube in 1857, a partially evacuated glass tube filled with various gases with a high voltage applied between two electrodes, causing the emission of light by fluorescence – see Fig.19. The technology was a predecessor to neon lighting. Warren De la Rue incandescent light globe 1815-1889 He enclosed a platinum wire in an evacuated glass tube in 1840, creating an early incandescent light globe. Giovanni Caselli fax machine 1815-1891 Invented the first practical fax machine in 1861, called the “pantelegraph” (“pan” meaning all in Greek). You can see a photo of it at: https://w. wiki/78ro Ernst Werner von Siemens 1816-1892 pointer telegraph, speakers, electric lifts etc Invented the “pointer telegraph”, in which a message was received by needles pointing at letters rather than Morse Code. In 1847, he established Telegraphen-Bauanstalt von Siemens & Halske to produce it (see the video at https://youtu.be/v8DZuT5c2CI). Siemens AG is still an innovative company today. In 1874, he received US Patent 149,797 for a “Magneto-Electric Apparatus” for “obtaining the mechanical movement of an electrical coil from electrical currents transmitted through it”. Although not intended as a loudspeaker, that is what became of the invention. Alexander Bell was granted a patent for the telephone in 1876, which incorporated a moving-iron type loudspeaker. Subsequently, Siemens received German patent 2355 in 1877 for an improved speaker design with a moving coil transducer, a diaphragm as a sound radiator and a trumpet form as a cone. This was adapted by A. L. Thuras and E. C. Wente for use by the Bell System as a loudspeaker. In 1880, Siemens built the world’s first electric lift. He was the first to use gutta-percha latex to insulate telegraph cables, making the 1866 transatlantic telegraph cable possible. He also invented a practical dynamo and an electric railway. He also developed a process for galvanoplasty, plastics with gold or silver plating. The unit of conductivity, the siemens (S), is named after him. Scott de Martinville 1817-1879 phono-autograph Invented the earliest known device to record audio waveforms in 1857, the phonautograph (see Fig.20). However, these waveforms could not be played back. In 2008, some waveform images from 1860 were digitised and converted back into sound, thus becoming the earliest known intelligible Above: Ernst Werner von Siemens also invented the trolleybus, usually powered from overhead lines. Source: https://w.wiki/7Arv Fig.18: Frederick Hale Holmes’ generator from Souter Lighthouse. Source: https://w.wiki/7A2K (CC-BYSA-4.0). 20 Silicon Chip Fig.19: a Geissler tube in the form of a piece of modern art. Source: https://w. wiki/78sf (CC-BY-2.0). Australia's electronics magazine Fig.20 (right): a phonautograph visual recording, c.1859. Source: https://w.wiki/78sb siliconchip.com.au recording of a human voice. They were made 28 years before Thomas Edison’s wax cylinder phonograph recordings. James Prescott Joule 1818-1889 magnetostriction and Joule heating An English physicist in the field of thermodynamics who established the concept of energy conservation, showing that heat, electricity and mechanical work were interchangeable. He discovered the relationship between current, resistance, and heat generation, which led to Joule’s Law. The unit of energy, the joule (J), is named after him. He also did work in the area of magnetostriction. In 1843, he discovered the relationship between the heat dissipated by a resistor and the current through it. Resistance heating due to a current flow became known as Joule heating. Léon Foucault 1819-1868 eddy currents Credited with the discovery of eddy currents or “Foucault currents” in 1855, although these were first observed by Dominique François Jean Arago (see his entry on page 16). Charles S. Bradley 1819-1888 three-phase generator Built the first three-phase generator in the USA in 1887. Moses Gerrish Farmer 1820-1893 duplex telegraphy, electric locomotives, bulbs He investigated telluric currents, low-­ frequency currents that travel through the Earth or sea of natural or artificial origin. In 1847, he demonstrated an electric locomotive that pulled two passengers on tracks, powered by a nitric acid battery. Along with William F. Channing in 1849, he demonstrated an improved electric fire alarm system in 1857. In 1852, he made repeaters for a telegraph system and, in 1853, patented a method to transmit four messages on one telegraph line simultaneously. In 1859, he co-created the self-­exciting dynamo. He invented a current regulator for his electric lamps in 1859. The “Wallace-­Farmer 8 horsepower” (6kW) dynamo was used by Thomas Edison in early lighting demonstrations. He made an incandescent light globe, also in 1859, using a platinum filament and lit his house with them in July 1859, the first house to be lit by electric lighting (not Joseph Swan’s, as usually claimed). John Stephen Woolrich 1820-1850 Woolrich Electrical Generator He built the Woolrich Electrical Generator in 1844, the first generator used for an industrial process, commercial electroplating (see Fig.21). The voltage and current ratings are unknown. Edmond Becquerel 1820-1891 photo-voltaic cell He produced the first photovoltaic cell in 1839 (see Fig.22). When light was directed onto the device, voltage and current were produced. The photovoltaic effect is now known as the Becquerel effect. John Wellington Starr 1822-1846 carbon & platinum filament incandescent globes Filed patents in 1845 for two types of incandescent light globe, one based on a carbon filament and the other on a platinum filament. They were never commercialised. Nevertheless, the patent is considered the first important one on the road to a commercial electric light globe. There is quite an extensive story to John Starr and many uncertainties; see siliconchip. au/link/abn9 Hermann von Helmholtz 1821-1894 Fig.22: the first photovoltaic device from Edmond Becquerel. Source: www.pveducation.org/pvcdrom/ manufacturing-si-cells/firstphotovoltaic-devices arranged to provide a region with a close-to-uniform magnetic field. A Helmholtz resonator is an enclosed volume with a neck that resonates at a specific frequency. They are incorporated in some car exhaust systems to eliminate noise at certain frequencies, and this phenomenon is also the cause of ‘wind throb’ in a car with open windows at certain speeds. See the video titled “How to build a Helmholtz Resonator DIY” at https://youtu. be/JUsyeBkNVEI Lord Kelvin 1824-1907 bandwidth, mirror galvanometer etc Also known as William Thomson, developed and patented a system for submarine telegraph cable in 1855, with calculations of the achievable data rate in relation to cable diameter and copper purity (bandwidth). He was also awarded patents for a mirror galvanometer (1858) and “siphon recorder” (1867) to record messages. Helmholtz resonator and coil Fig.21: the Woolrich Electrical Generator, the first commercial generator. Source: https://w.wiki/78sc (CC-BY-SA-4.0). siliconchip.com.au Studied electrical resonance and invented the Helmholtz resonator during 1869-1871. He saw mechanics, heat, light, electricity and magnetism as a manifestation of a single force and published his ideas in “On the Conservation of Force” (in German) in 1877 – see siliconchip.au/link/abna Helmholtz also invented the Helmholtz coil, which is two electromagnets Australia's electronics magazine Lord Kelvin resting on a binnacle (housing for a ship’s compass) while holding a marine azimuth mirror. Source: https://w.wiki/7Arz October 2023  21 Thomson’s submarine telegraph system could send one character every 3.5 seconds. He also significantly contributed to thermodynamics; the absolute temperature unit Kelvin (K) is named after him. He invented the Kelvin balance that allowed the unit of current (the ampere) to be precisely defined. Gustav Robert Kirchhoff 1824-1887 Kirchhoff’s circuit laws He made significant contributions in the fields of electrical circuits, spectroscopy and the emission of blackbody radiation by heated objects. Kirchhoff’s circuit laws from 1845 are foundational to electrical engineering and physics. They allow an electrical network (circuit) to be analysed to determine the expected currents and voltages. Zénobe Gramme 1826-1901 Gramme machine (DC dynamo) In partnership with Hippolyte Fontaine, they built and manufactured an improved DC dynamo around 1873, called the Gramme machine, which produced smoother DC and higher voltages than prior machines. The duo also worked on other electrical devices. In 1873, he and Fontaine discovered that if the dynamo were connected to a DC supply, it would work as a much more powerful electric motor than any others at the time, which were of no practical use. Willoughby Smith 1828-1891 photo-conductivity Discovered photoconductivity in 1873 (when a material becomes more conductive upon exposure to light) in selenium. Sir Joseph Wilson Swan 1828-1914 first successful light globe Started experimenting with incandescent light globes in 1860, but was hampered by the lack of a good vacuum pump and a suitable power supply. In 1878-1879 he demonstrated the first incandescent light with a carbon filament in an evacuated globe, and he is regarded as the inventor of the first successful globe (see Fig.23). His house was claimed to be the first house to have electric lighting, but Moses Gerrish Farmer’s was likely first (see page 21). In 1881, he installed 1200 light globes in the Savoy Theatre in London, the first public building to have them. They were powered by an 88kW generator. Thomas Edison independently 22 Silicon Chip Fig.23: These carbon filament bulbs show the blackening effect. This is due to the evaporated carbon condensing on the inner surface of the bulb. Source: https://w.wiki/7As8 developed the light globe, and both men obtained patents in 1880. Swan sued Edison. This led to a joint company being formed in Great Britain in 1883, the Edison & Swan United Electric Light Company (“Ediswan”), to exploit the inventions. Edison and Swan produced successful light globes, but there were many ideas for globes before them, starting with Volta. David Edward Hughes 1830-1900 printing telegraph and microphone Developed a printing telegraph system in 1855. In 1878, he described electronic carbon-powder-based sound pickups called “transmitters”, then being developed for telephones. He demonstrated how they worked, superseding the prevailing theory of the time and coining the term “microphone”. He developed a type of microphone but never patented it, thinking the work should be available for the benefit of all. In 1879, he likely detected radio waves before Heinrich Rudolf Hertz did in 1887/1888, but attributed the phenomena to electromagnetic induction rather than radio waves. James Clerk Maxwell 1831-1879 Maxwell’s equations Discovered that electricity, magnetism and light were different manifestations of the same thing. He produced Maxwell’s equations in 186162, which are the basis of electrical circuit and light theory. They explain how electric and magnetic fields relate. Oliver Heaviside produced the modern form (the Maxwell-Heaviside equations). His work combining all previous observations, experiments and equations into a consistent electromagnetic theory set the foundation for much of Australia's electronics magazine Fig.24: a Crookes tube, the basis of the cathode ray tube (CRT). Source: D-Kuru/Wikimedia Commons – https://w.wiki/7BiD 20th-century physics and led to the era of modern physics. Henry Woodward & Matthew Evans incandescent light globe Together they obtained a Canadian patent in 1874, then US Patent 181,613 in 1876 for an incandescent light globe that used a carbon filament in a nitrogen-­filled enclosure. They did not have enough money to develop their invention, so they sold the patents to Thomas Edison in 1879. Sir William Crookes 1832-1919 Crookes tube – the basis of X-ray tubes Invented the Crookes tube (Fig.24) around 1869-1875. It is a partially evacuated glass tube with an anode at one end and a cold cathode at the other that produces cathode rays. The shape of the anode causes a shadow to be projected by the cathode rays (electrons), some of which are blocked by the shape, while others that pass to the outside. It is the basis of X-ray tubes and the cathode ray tube (CRT) as was commonly used for TVs, computer screens, radar displays and oscilloscopes. Some CRTs used heated cathodes. John Dixon Gibbs 1834-1912 power transformer With Lucien Gaulard, he demonstrated a power transformer in 1881 and obtained US patent 351,589 in 1886. While transformers were not a new idea, this was the first that could handle power at industrial levels. Johann Philipp Reis 1834-1874 Reis telephone and speaker Constructed a type of telephone in 1861 with a range of 100m (Fig.26). It incorporated a microphone based upon a parchment diaphragm that altered the electrical resistance between two contacts when it vibrated, siliconchip.com.au one of which was dipped in a drop of mercury. He also made a speaker that produced reasonable but weak sound, it was based on magnetostriction (ferromagnetic materials changing their shape when subjected to a magnetic field). Reis’ device could not reproduce speech intelligibly, so his patent was not upheld in a dispute with Alexander Graham Bell. However, David Edward Hughes later reported good results with the Reis telephone. Around 1947, the Reis device was tested by the British company STC, which confirmed it could transmit and receive speech, albeit faintly. The patent was partly invalidated because of a mistake in describing how the microphone worked; Reis said it worked by making and breaking electrical contact when it actually varied the resistance. Elisha Gray 1835-1901 Fig.25: the original writing and received copy on the Elisha Gray telautograph. Source: Popular Science Monthly, Volume 44, 1893-94. Musical Telegraph, telephone etc Invented an improved printing telegraph in 1872 (US patent 132,907). He also invented a “Musical Telegraph” that transmitted single musical tones over a telegraph link in 1874 (US patent 173,618). Oscillating steel reeds controlled by electromagnets produced the tones. See the video titled “Elisha Gray’s Musical Telegraph” at https://youtu.be/YxxsTdjT7PA Gray secretly built a prototype telephone in 1876. Alexander Graham Bell’s lawyer got to the patent office shortly before Gray’s lawyer; thus, Bell got credit for the invention. The true inventor of the telephone is still hotly contested. Gray is, however, known for inventing one of the first electric musical instruments (Fig.27). In 1887, he invented the telautograph, a precursor to the fax machine, although he is thought to have conceived the idea as early as 1874. He patented it in 1888 (US patent 386,814). A user’s handwriting was transmitted using a stylus attached to a mechanism that transmitted the stylus’ coordinates over a two-wire telegraph circuit (see Fig.25). The system became very popular. Fig.26: a Reis telephone consists of a transmitter, receiver (C) and a glass dome, all powered by a battery (B). siliconchip.com.au Australia's electronics magazine A telautograph can be seen in operation in the 1956 movie Earth VS The Flying Saucers on YouTube: https:// youtu.be/JCdnv3AP0eM?t=3683 William Grylls Adams 1836-1915 selenium produced an electric current Together with his student Richard Evan Day, they discovered that a platinum/selenium junction produced a current in 1876. Oberlin Smith 1840-1926 recording sound He proposed a method for recording sound by magnetic means in 1888. A thread such as cotton was coated with Fig.27: Elisha Gray’s Musical Telegraph from 1876. Source: https:// americanhistory.si.edu/collections/ search/object/nmah_703475 October 2023  23 or contained a magnetic powder or short lengths of fine wire, which were then magnetised by the current from a microphone source. His ideas were implemented by Valdemar Poulsen (see his entry next month) but it is unknown whether Poulsen was familiar with Smith’s work. Sir Hiram Maxim 1840-1916 electric lamps While famous for designing weapons, he also made significant contributions to the development of electric lighting, including improved methods of carbonising and manufacturing filaments for electric lamps. John William Strutt 1842-1919 Rayleigh scattering & waveguides Also known as Lord Rayleigh, made the first theoretical analysis of electromagnetic waves in a metal cylinder (waveguide) in 1897. He discovered what is now known as Rayleigh scattering, along with many other discoveries. Nikolay Benardos & Stanisław Olszewski arc welding They used a carbon arc to soften metals to a plastic state and, in 1881, demonstrated the first practical arc welding. Édouard Branly 1844-1940 coherer (radio signal detector) Invented the coherer, the first detector of radio signals in 1890, based upon the work of Onesti (see his entry next month). It consisted of iron filings in an insulating tube with two electrodes. Tivadar Puskás de Ditró 1844-1893 telephone and multiplex switchboard Invented the telephone switchboard in 1876. The first one was built by the Bell Telephone Company in 1877. In 1887, he invented the multiplex switchboard for more efficient resource sharing. Augustus Floyd Delafield 1845-1927 homopolar motor He received US patent 278,516 in 1883 for a “dynamo-electric machine” based on Faraday’s homopolar motor design. The video titled “The Homopolar Generator” at https://youtu.be/ cQ5Ueouk_VY shows how it works. Sir Mark Oliphant built a famous homopolar generator at Australian National University (ANU). It was one of the largest ever built and could deliver currents of 2MA. It operated from 1962 to 1986 and was designed to produce extremely high current pulses for applications such as rail guns. Wilhelm Conrad Röntgen 1845-1923 X-rays Was investigating vacuum tube equipment produced by others in 1895 when he discovered X-rays. He was performing experiments with a Crookes tube and fortuitously had some barium platinocyanide on his hand, a chemical known to fluoresce in UV light. He noticed it glowing out of the corner of his eye, an area of the eye that’s very sensitive to light. He had the barium platinocyanide because of experiments he was doing with a Lenard window tube, a Crookes tube with a thin window to allow some electrons to escape into the atmosphere. Alexander Lodygin 1847-1923 lamp. He sold the patent to General Electric in 1906. Pavel Yablochkov 1847-1894 carbon arc lamp Invented a kind of carbon arc lamp in 1876 called the “Yablochkov candle”. It would run for about two hours and could only be used once; it needed a large power source, produced a buzzing sound, UV rays, carbon monoxide and was a fire hazard. To power his lamps, Yablochkov invented a type of transformer based on Faraday’s discovery of induction to supply the required AC voltage for the lamps. The use of transformers to supply different voltages later became the basis of AC power distribution systems. Galileo Ferraris 1847-1897 polyphase alternator and induction motor He worked in the area of rotary magnetic fields in 1885. Such fields can be provided by a polyphase alternating current driving a system of coils or a single phase with windings arranged in a particular manner. His work led to the development of the polyphase alternator (effectively an AC motor operating in reverse) and the first induction (asynchronous) motor (Fig.28), but he did not patent it. He published his research on motors in 1888, just two months before Nikola Tesla obtained a patent for such motors. The invention of the polyphase alternator was a crucial event in the history of electrification. Alessandro Cruto 1847-1908 high-purity graphite light globe filaments Started experimenting with light globe filaments in 1880 and devised a carbon and metal filament lamps Fig.28: the world’s first AC motor from 1895 by Ferraris. Source: https://w. wiki/78se 24 Silicon Chip Later known as Alexandre de Lodyguine, obtained Russian and European patents in 1872 for a carbon filament lamp. In the 1890s, he invented some metal filament lamps and obtained US patent 575,002 for a tungsten filament Australia's electronics magazine Alexander Bell also co-founded AT&T. Source: https://w.wiki/7AsL siliconchip.com.au process of making high-purity graphite filament, which he demonstrated at the Electricity Expo in Munich in 1882. This filament was more efficient than that used in Edison’s globe and produced a white light, unlike Edison’s yellow light. Also, it lasted for 500 hours, while Edison’s original version only lasted 40 hours. He established a factory in Alpigano, Italy, producing 1000 globes per day. After disagreements, he resigned from the factory and, after many changes of hands, it was acquired by Philips in 1927. Alexander Graham Bell 1847-1922 telephone, photophone etc Bell is most famous for his work in developing telephony. In 1875, he developed an acoustic telegraph to send multiple telegraph messages on one line (ie, a multiplexing method). He filed US patent 174,465 in 1876 for the telephone, slightly before Elisha Gray (as noted earlier). Bell got his “instrument” (as he called it) to work for voice only three days after he got the patent, using a liquid transmitter (microphone) of Gray’s design; his first famous words on the device were to his assistant, Thomas Watson, “Mr Watson, come here, I want to see you”. Despite his achievements with the telephone, Bell regarded his greatest achievement as the photophone in 1880. This enabled voice transmission on a modulated light beam that travelled 213m in one experiment. It had no real application until the invention of the laser (1960) and the optical fibre (1965) for optical transmission of information. It was jointly Some of the oldest audio recordings A collection of early sound recordings and associated links are available at siliconchip.au/link/abni The following link is to a recording made by Alexander Graham Bell in 1885. It was recovered optically by 3D imaging the grooves of the wax disc recording: siliconchip.au/link/abnj You can also see a video where the author searched through old texts to find sound representations and digitally converted them to the original sounds at https://youtu.be/TESkh3hX5oM invented with his assistant Charles Sumner Tainter. Thomas Alva Edison 1847-1931 microphones, acoustic telegraphy, fuse etc Edison was a prolific inventor and entrepreneur. In 1873, he demonstrated the varying resistance of carbon grains in response to pressure and built a rheostat based on that idea, but abandoned it due to sensitivity to vibration. It was useless for its intended purpose in telegraphy but came in handy later for carbon powder microphones, which he tested in 1876. In 1875, he performed experiments in acoustic telegraphy, the name for multiplexing messages on telegraph lines, receiving US patent 182,996 in 1876. He filed for US patents 474,230, 474,231 & 474,232 for a “Speaking telegraph” in 1877, awarded in 1892. The patents took so long to be granted due to the competing claims of Alexander Graham Bell, Emile Berliner, Elisha Gray, Amos Dolbear, J.W. McDonagh, G.B. Richmond, W.L.W. Voeker, J.H. Irwin, Francis Blake Jr and others. In 1877, he invented a phonograph. The device recorded on tin foil and could only be used a few times; nevertheless, he gained fame for it. In 1878, he demonstrated the machine in Washington, DC and was celebrated as a genius. He received US patents 200,521 and 227,679 for it in 1878 and 1880, respectively. In 1878, he established the Edison Electric Light Company and said, “We will make electricity so cheap that only the rich will burn candles”. In 1879, he filed and, in 1880, received US patent 223,898 for an “Electric-lamp”. In 1880, he established the Edison Illuminating Company for electricity distribution in New York and, in 1882, opened the Pearl Street Station (600kW, 110V DC). In the 1880s and 1890s, there was the “War of the Currents”, the debate about whether electricity distribution systems should be DC or AC. Edison supported DC and saw AC as dangerous and unworkable. Edison invented a fuse in 1890 to protect his electrical distribution system. Next month That’s all we have room for in this issue. We will pick up where we left off in the second article next month, completing our chronological list of SC inventors. A replica of the upstairs level of Edison’s Menlo Park lab. Source: https://w. wiki/7AsR Also see our twopart series on Edison (September & October 2006; siliconchip.au/ Series/79). The Edison light bulb enclosed in a cage. Source: https://w.wiki/7AsG siliconchip.com.au Australia's electronics magazine October 2023  25