Why is the electrical engineering major called electrical? I have studied electrical engineering for so many years, but I have never thought about this problem~ Today I was stumped by a high school student from the neighbor’s house. After thinking about it carefully, I think this topic is very meaningful. I hope that some friends can discuss it together. .
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electrical concept
Electrical (electrical, electrical power and equipment)
It is a general term for disciplines or engineering fields such as the production, transmission, distribution, use, and electrical equipment manufacturing of electric energy.
It is a science to create, maintain and improve limited space and environment by means of electric energy, electrical equipment and electrical technology.
Covering three aspects of electric energy conversion, utilization and research, including basic theory, application technology, facilities and equipment, etc.
And what is the "electrical appliance" that is often confused by laymen?
electrical appliance
Refers to all appliances that use electricity.
Professionally speaking: electrical devices, equipment and components used to connect and disconnect circuits and transform circuit parameters to realize control, adjustment, switching, detection and protection of circuits or electrical equipment.
In layman's terms: some commonly used household appliances that provide convenience for life, such as televisions, air conditioners, refrigerators, washing machines, various small appliances and so on.
Next, let us walk into "electricity" and get to know "electricity".
Electrical Provenance
Viewpoint 1:
The word "electricity" should be the translation of electric fluid by foreign missionaries in the late Qing Dynasty. For details, please refer to Lei Yinzhao's article "Etymology of "Electricity"". Here I will briefly explain it.
"Electricity" may have originated from the book "Philosophical Almanac, 1851" translated by American missionary D. J. Macgowan, which is also the earliest known work on electromagnetism in Chinese.
At that time, it was not long before Faraday discovered the phenomenon of electromagnetic induction, and electrons were not discovered by Thomson until decades later. At that time, the mainstream theory of electricity in the scientific community was the fluid theory of electricity. The phenomenon is explained as the motion of an electric fluid. These include the two-fluid hypothesis proposed by Charles du Fay and the one-fluid hypothesis proposed by Benjamin Franklin (according to today's point of view, both are essentially positive and negative charges).
"Electricity" is Ma Gaowen's translation of electric fluid when he translated and introduced the mainstream knowledge of electricity in the West at that time. Ma Gaowen used "qi" to translate fluid, perhaps not only considering the flow characteristics of qi, but also considering that at that time, electricity, like "qi" in ancient Chinese philosophy, was a mysterious phenomenon that existed in everything.
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How to explain it depends on your rigorous discussion and research.
Point two:
At the beginning of Western industry, power machinery was driven by steam turbines, and later came electricity, so "electricity" began to refer to industrial power, but now there is no steam turbine, so it is simply used to refer to electricity . The term "electrical" is already used, so keep using it!
The gas in electricity refers to "compressed air". In industrial automation, there are three types of equipment that need to be moved: electric, pneumatic, and hydraulic. Electric and pneumatic are the most widely used power sources, and they are used in combination to complete automation. So it is called: electrical automation.
Point three:
There are two reliable explanations I've heard of the origin of electrical names:
Explanation 1: Ancient Chinese cognition
Electricity is a natural phenomenon. In ancient times, people discovered its existence through lightning. In ancient China, the ancients believed that the phenomenon of electricity was generated by the excitation of yin and yang. "Shuowen Jiezi" has "electricity, yin and yang are excited, and rain follows Shen". "Zihui" has "Thunder comes from Hui, and electricity comes from Shen. Yin and Yang use the thin back to form thunder, and Shen to vent to form electricity." The ancients' explanation (or theory) of electricity was explained through "qi", which is electricity.
China first used the theory of qi to explain the attraction phenomenon of electricity, which appeared in "Lunheng" written by Wang Chong of the Eastern Han Dynasty.
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Explanation 2: Modern scientific understanding
Modern science believes that matter is composed of atoms, and atoms are composed of nuclei and extranuclear electrons. The nucleus is positively charged, the electrons are negatively charged, and the atom is electrically neutral. However, under some physical effects (there are mainly 3 types of methods: frictional electrification, contact electrification, and induction electrification), some atoms will lose some extranuclear electrons, thus showing positive charge; some atoms will gain some electrons, thus showing negative charge .
Electrons are particles with the smallest charge. Physicists call the smallest charge the elementary charge, denoted by the symbol e (e=1.6x10⁻¹9). The amount of charge carried by any charged body is an integer multiple of e. The flow of charge creates an electric current. This is almost the most accurate understanding of electricity in modern physics.
Based on this logic, we know that the essence of electricity is the movement of electrons, and electrons are microscopic particles that move at high speeds (close to the speed of light 3×10⁸m·s⁻¹) in such a small space (diameter about 10⁻¹⁰m) ) movement, the movement of electrons outside the nucleus is different from the movement of macroscopic objects, there is no definite direction and trajectory, and the electron cloud can only be used to describe the size of its chance (probability) to appear somewhere in the space outside the nucleus.
According to the uncertainty principle in quantum mechanics, it is impossible for us to accurately measure the position and speed of the electron at a certain moment at the same time, nor can we describe its trajectory. Therefore, people often use a model that can represent the chances of electrons appearing in various places outside the nucleus within a certain period of time to describe the movement of electrons outside the nucleus.
The resulting three-dimensional image of this model looks like the space around the nucleus has an electronegative atmosphere due to the movement of electrons. Describe the probability of electrons appearing in various regions around the nucleus. It can be represented by the electron cloud density (the thickness of the negative electric atmosphere) in the image, and the probability is represented by different shades. The result is like the mist formed by electrons around the nucleus, so it is also called electron gas, that is, electricity.
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It can be seen that electricity covers all physical phenomena related to electronic movement, including strong electricity and weak electricity. Electricity refers to all electricity. Therefore, electrical engineering in foreign universities covers power engineering (strong electricity), electronic engineering (weak current), information engineering (weak current). But in China, electricity refers specifically to power engineering.
Because the origin of electricity began with the study of lightning and other strong electricity phenomena, mainly based on power, and later began to use electricity to represent signals, thus resulting in informatics, electronics, computers, etc. These signal-based technical categories, That is, electrical should include two levels of power and signal. I think this is the most scientific and reliable explanation of electricity.
Viewpoint 4:
Gas invisible device visible. It just feels that electricity seems to have a wider meaning, including both tangible and intangible, because electricity seems to be the movement of electricity, and after it is concretized, there are electric motors, electrical appliances, and electronics.
Electronics, electrical appliances and electricity all belong to electrical engineering. It is an abstract concept that does not specifically refer to a certain device or device, but refers to the entire system and the category of electronics, electrical appliances and electricity.
Electrical is an engineering vocabulary
electric
basic translation
English: electric
Japanese: 电気 (でんき)
Electricity is a science to create, maintain and improve limited space and environment by means of electric energy, electric equipment and electric technology, covering three aspects of electric energy conversion, utilization and research, including basic theory, applied technology, facilities and equipment, etc.
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The air flow in the usual concept means that in modern industry, electrical signals are often used to control input and output, and air flow is used to control the work of mechanical parts. For example, the simplest one is: air cylinder, which uses electricity to control the on and off of the valve, and then determines Whether to supply air to manipulate the mechanical part, so electricity and air are often referred to together as electricity.
Electrical engineering can actually be understood in this way. Physical quantities such as current, voltage, and current flow in the transmission line, which is equivalent to the movement of air in the human body. A circuit or even a power grid can be regarded as a human body, and the elements inside are current, voltage, and current can be regarded as Qi, exchanging energy with the outside world! ! The electrical engineering we are talking about is also a human engineering project, controlling the skeleton frame of this person, controlling the flow and transformation of its Qi! !
Point five:
For the understanding of "qi", I think it is gas. Undergraduate students in power electronics have no idea about this. After studying for graduate school, they turned to high voltage and insulation technology to discover the huge role of gas in electricity. The simplest example is the air switch. It works because it is in the air. As an insulating medium, air is the decisive factor that determines whether it can work.
In the process of studying insulation, it includes gas insulation, solid insulation and liquid insulation. Gas insulation has the best self-recovery property, and the cheapest insulating medium is air. This is how the air switch was born. In addition to air, sulfur hexafluoride gas is also a hot topic of research now. The dielectric strength is 2.5 times that of air, and the arc extinguishing ability is 100 times that of air. Therefore, it is in the introductory knowledge of the high voltage field.
The discharge theory about gas is all discussed as the first chapter, and the most classic Townsend theory and streamer theory are also about gas insulation. It can be said that the study of gas insulation is half of the study of high voltage, and without high voltage, there will be no transmission and distribution of electric energy, and the entire power supply system will not exist. Can we understand the importance of "Qi" now?
