Gustav Kirchhoff formulated a number of principles or laws, which fall into three basic categories: electrical circuits, spectroscopy and thermochemistry. Kirchhoff proposed two electrical circuit laws. His current…
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第一次提及《时间箭》是亚瑟·埃丁顿爵士。他是著名的英国天体物理学家，他于1919年5月进行了一次探险……
The postThe arrow of time and the 2nd law of thermodynamicsappeared first onTest & Measurement Tips.
海因里希·赫兹的书,他展示了existence of electromagnetic waves predicted by James Clerk Maxwell, died after a long illness in 1864 at the age of 36. In 1930…
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The Standard Model is a remarkably successful synthesis of much that we know about electromagnetic, weak and strong nuclear forces. It also classifies all known subatomic particles. As…
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欧文薛定谔是第一个使用“entanglement” (Verschränkung), in a letter to Albert Einstein. His intent was to describe the connection between two particles that…
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It has been said of Paul Dirac (1902-1984) that he was able to conjure laws of nature from pure thought. His method was not experimental, but instead theoretical….
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In many ancient mythologies, lightning and the associated thunder crash were seen as mechanisms for divine retribution. Though we are well beyond that view, the public still has…
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Simply stated, the elementary particles that constitute matter are fermions and the elementary particles that constitute energy are bosons. Fermions have half-integer (1/2, 3/2, 5/2 …) spin while…
The post沃尔夫冈·保利和排除原则appeared first onTest & Measurement Tips.
Werner Heisenberg (1901-1976) propounded (as applicable to quantum mechanics) his Uncertainty principle in 1927. It stated that there is a fundamental limit to the precision with which certain…
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There is something almost comical about a waveguide – the notion that electromagnetic signals or usable power could pass through a hollow pipe and that techniques appropriate to…
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Coaxial cable receives its name because all its parts — outer jacket, grounded return conductor, dielectric layer and inner metallic pin — share a common axis. Many installers…
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Georg Simon Ohm (1789-1854) was an educator, mathematician and theoretician, but above all he was an experimenter. Ohm’s law, relating electrical force, current and resistance in a circuit,…
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William Sturgeon (1783-1850) is an unfamiliar name in most households, but his experiments and the instruments that he built were central in the annals of electrical engineering. He…
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Hans Christian Ørsted (1777-1851) was for most of his life deeply immersed in the philosophy of Immanuel Kant, whose major work, The Critique of Pure Reason, published when…
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Characteristic of his time, Pierre-Simon Laplace (1749-1827) published a comprehensive review of the scientific work done by his predecessors with an overlay of his new mathematical interpretation. Titled…
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In the early eighteenth century and before, England had long been the scene for most of the important research and theorizing about the nature of electricity and magnetism. The…
The postCharles-Augustin de Coulomb和收费单位appeared first onTest & Measurement Tips.
Who was the first electrical engineer? Thomas Edison, James Clerk Maxwell, William Gilbert? None of the above. Miletus, near Turkey’s west coast, today lies in ruins but it…
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William Gilbert, a practicing physician who attended Queen Elizabeth I throughout the last difficult years of her reign, was most noted in his time as a keen astronomical…
The post电力之父，威廉·吉尔伯特appeared first onTest & Measurement Tips.
1703年，艾萨克·牛顿（Isaac Newton）最近被任命为皇家学会主席，希望振兴那个著名的英国科学家的稳定组织。为此，他任命了自己的实验室…
The postHauksbee and the generation of static electricityappeared first onTest & Measurement Tips.
Stephen Gray, astronomer, instrument maker and electrical experimenter, lived in England from 1666 to 1736. Despite challenges of ill health and intermittent poverty, his systematic investigation of electrical…
The postThank Stephen Gray for wire and insulatorsappeared first onTest & Measurement Tips.
The first step in transmitting radio-frequency signals through space is to create a pure carrier at the transmitter. This electrical wave must be of stable, unvarying amplitude, frequency and phase….
The postBasics of digital modulationappeared first onTest & Measurement Tips.
By David Herres Typical real-world phenomena (most sensor output, acoustic information in air-pressure variations, temperature fluctuations, etc.) are analog rather than digital in nature. If translated into an…
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By David Herres We straddle two realms, analog and digital. The output of a sensor, musical instrument, the human voice, and most of the signals that originate in…
The postBasics of analog-to-digital convertersappeared first onTest & Measurement Tips.
By David Herres Waveforms other than those that are pure sine waves or sinusoidal will have a portion of their energy in frequencies other than the fundamental. These frequencies…
The postBasics of harmonicsappeared first onTest & Measurement Tips.
戴维·赫雷斯（David Herres）的非sin肌波形不是正弦波，也不是正弦波（正弦状）。这听起来像是一个较小的区别，但是…
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