- branch of science and technology related to
using electrical and magnetic
phenomena for energy conversion,
obtaining and changing chemical
composition of substances, production and processing
materials, communication,
covering the issues of obtaining,
conversion and use
electrical energy in practical
human activity.
Historical reference.
The emergence of electricitypreceded by a long period
accumulation of knowledge about electricity. Total
200 years ago, the first experiments on
practical applications of electricity, and
it's hard to imagine even one
industry that does not use
Electric Energy.
We are proud to develop
electrical engineers have made an invaluable contribution
Russian scientists. Their work has always been
original, closely linked to practice
and were of global importance. Historical reference.
1711-1765
Back in 1753 our
genius compatriot academician Mikhail
Vasilyevich Lomonosov
in the speech “A word about phenomena
air, from the electric force occurring,
spoken in
Petersburg on the act
Academy of Sciences, outlined
their observations on
atmospheric electricity and made a series
theoretical and
practical conclusions. Historical reference.
In their research
M. V. Lomonosov opened
the physical nature of atmospheric electricity, pointed out the possibility
protection against injury
lightning with the help of a lightning rod, was the first to suggest the electromagnetic nature of the northern
radiance, etc. Historical reference.
1711-1753
The Russian academician worked together with M.V. Lomonosov
Georg Wilhelm Richmann. He
started his research in
the field of electricity in 1745
d. He deserves the credit
the creation of the first electrical device - the "electric pointer", which allowed
produce quantitative
electricity measurements. This
the device was used for
studying
atmospheric
electrical
phenomena. Historical reference.
Russian academician
F. W. Aepinus in 1759
suggested connection
electrical and magnetic
phenomena. Among his
inventions include
electrophorus (simple
device for receiving
electricity) and
capacitor.
1724-1802Historical reference.
1761-1834
Relying on Scientific research M. V. Lomonosov,
G. V. Richmann, F. W. Aepinus and
other scientists, academician
Vasily Vladimirovich
Petrov made the most important
discoveries in the practical application of electricity. He built one of
the largest galvanic batteries of its time and with
with its help, a number of
outstanding research. Historical reference.
In 1802 V. V. Petrov
received for the first time in the world
electric arc.
V. V. Petrov came up with the idea of using
electric arc for
lighting. He wrote
that with the help
open to them
electric arc
"dark peace is pretty
be clearly lit
Maybe". Historical reference.
V. V. Petrov was the first in
arc flame melted
metals, welded
pieces of metal. This
widely used
around the world and in
our days. Historical reference.
V. V. Petrov for the first time
applied insulation
metal
conductors. He
researched a particular
the glow of bodies, so
called
luminescence. Historical reference.
Widely known for his work on
generating electricity through friction
research
electrical
phenomena in gases
and many others.
In the TOE laboratory Historical reference.
A contemporary of V.V.
Petrov was famous
Russian scientist Pavel
Lvovich Schilling. In 1812
P. L. Schilling applied
electricity to explode
underwater mines. Our
Motherland was the first
the country in which
practically used
electromagnetic telegraph,
invented
P. L. Schilling in 1832
1786-1837Historical reference.
1804-1865
1801-1874
Of particular note are the Russian academicians Boris
Semenovich Jacobi and Emil Khristianovich
Lenz. Their discoveries are still widely used today.
V various industries electrical engineering. Historical reference.
B. S. Jacobi created in 1834 the first electric
engine. More than 170 years ago (in September 1838) according to
A boat with 14 passengers passed the Neva against the current. In this
the boat was equipped with an electric motor designed
B. S. Jacobi
together with
E. H. Lenz. Historical reference.
electroplating
B. S. Jacobi discovered in 1838
electroplating and electroplating - the beginning of practical
whom the use of chemical
the action of electric current; created the first direct-printing telegraph
apparatuses (1850), proposed
way to isolate underground
wires, invented the rheostat and
much
other. Historical reference.
The widest
famous
works of E. Kh. Lenz on
electromagnetism. He
formulated the rule
allowing to determine
direction
induced current in
conductor (Lenz's rule).
E. H. Lenz, regardless of
English physicist Joule
discovered thermal action
current (Joule-Lenz law). Historical reference.
B. S. Jacobi and E. H. Lenz are considered the founders of the theory electrical machines. They own
part of such a remarkable discovery as the phenomena
"reversibility
machines”, i.e.
ability
generator
to work in
quality
electric motor,
and vice versa. Historical reference.
(1847-1894)
Talented Inventor
Pavel Nikolaevich
Bullseye using an arc
Petrov, gave the world the first
electric light - "candle
Yablochkov. He is the first
understood the benefits
AC, and boldly
put it into practice. P.N.
Yablochkov designed and
practically used
transformers. Historical reference.
Talented Inventor
Pavel Nikolaevich Yablochkov
using the Petrov arc, gave
the world's first electric
light - "Yablochkov's candle".
He was the first to understand
benefits of variable
current, and boldly introduced him into
practice. P. N. Yablochkov
designed and
practically used
transformers. Historical reference.
(1847-1923)
The work of P. N. Yablochkov was continued by the inventor-compatriot Alexander Nikolaevich
Lodygin. In 1873 he creates
an electric incandescent lamp with a carbon filament, and in 1890 -
a lamp with a metal thread.
A. N. Lodygin "the first
took the incandescent lamp out of the physics office and onto the street. Historical reference.
(1839-1896)
The largest Russian scientist
Alexander Grigorievich
Centuries in detail
explored magnetic
phenomena and opened a series
laws used in
calculation of electrical
machines. When researching
photovoltaic
effect created
photocells. Historical reference.
Almost simultaneously with P.N.
Yablochkov original
transformer design
proposed Russian self-taught physicist Ivan Filippovich
Usagin. Demonstration
Usagin transformers on
industrial exhibition in 1882
city in Moscow caused “loud and
unanimous approval."
(1855-1919)Historical reference.
Physicist Nikolay
Alekseevich Umov decided
(in 1874) the most difficult
theory problem
electricity is a problem
electrical movement
energy.
(1846-1915)Historical reference.
Military electrical engineer Fedor Apollonovich
Pirotsky proposed to use the flow of water for
receiving electricity,
(1845-1898)
and also produced
numerous experiences in
transmission of electrical
energy for large
distances. Historical reference.
In 1874, he practically carried out
transmission of electrical power
about 6 horsepower per distance
up to 1 km. F. A.
Pirotsky
created the world's first
electric tram and
carried out successful
experience in use
this tram for
movement.
August 22, 1880 at 2 pm on the Sands in St. Petersburg. Historical reference.
Research questions
transmission of electricity to
traveled long distances
Dmitry Aleksandrovich
Lachinov. He also deeply explored the issues of parallel
inclusion of lamps in a circuit of one
generator.
D. A. Lachinov invented the device
for power measurement
electric motors, introduced a number
significant changes in
design of spotlights, etc.
(1842-1902)Historical reference.
(1862-1919).
Creator of the first three-phase gene
rotor, motor and transformer
ra was an innovative engineer Mikhail
Osipovich Dolivo-Dobrovolsky. Thanks to inventions
M. O. Dolivo-Dobrovolsky
transmission became possible
electrical energy for large
low-loss distances and,
hence the electrification
huge territories. He is
created devices such as
wattmeter, phase meter, frequency meter. Historical reference.
The greatest discovery of modern times was the discovery
Alexander Stepanovich
Popov. This discovery
marked the beginning of a new
electrical engineering industries
radio engineering.
Broadcasting, radio communication,
television, telecommand,
radar, radio navigation would be
impossible without a brilliant discovery
A. S. Popova.
(1859-1906).Historical reference.
The greatest discovery of modernity
was the discovery of Alexander Stepanovich
Popov. This discovery marked the beginning
new branch of electrical engineering -
radio engineering.
Broadcasting, radio communication,
TV,
telecontrol,
radar,
radio navigation would be
impossible without genius
discoveries of A. S. Popov. Historical reference.
Russian inventors
Nikolai Nikolaevich Benardos and
Nikolai Gavrilovich Slavyanov
used an electric arc for welding and
metal cutting.
(1842-1905)
(1854-1897)Historical reference.
The growth of the electrical industry was facilitated by the unprecedented flourishing of domestic and foreign science. Instead of lone scientists who spent their scientific work in semi-handicraft laboratories, there appeared scientists working
in numerous research
institutes and academies. Historical reference.
Greatest triumph
domestic science was launched
in 1954 the first in the world
industrial power plant
.
at nuclear
.
useful energy
.
power
.
5000 kW. Electricity is firmly established
into our life. Not today
areas of industry and agriculture,
.
where not used.
would be electric.
energy. We can't
.
we are safe
.
exist without
.
electricity and
.
Houses. All electrical appliances require
competent treatment. Their
repair, maintenance and
operation is not possible
without basic knowledge of electrical engineering. Studying
electrical engineering is impossible
without such fundamental
sciences like mathematics and
physics. successful
mastering theoretical
fundamentals of electrical engineering
facilitate learning
special disciplines on
senior courses. Thank you for your attention
complex systems and networks”:
Microprocessors and
microprocessor
systems;
Construction
computer facilities
Teacher-Ivanov Pavel
Vitalievich Electrical engineering helps to master disciplines.
For the specialty 230101 "Computers,
complex systems and networks”:
Peripheral
devices
Teacher - Sizova Olga
Alexandrovna Electrical engineering helps to master disciplines.
For the specialty 230101 "Computers,
complex systems and networks”:
Automatic
design
digital devices;
Design
automated
control systems;
Development
instrumental
funds
Teacher-Fedorov Alexey
Aleksandrovich
equipment":
Contactless
electrical
devices
Teacher - Alexander Butorin
Grigorievich Electrical engineering helps to master disciplines. For specialty 140613 " Technical operation And
maintenance of electrical and electromechanical
equipment":
Electrical
cars;
Electrical
equipment;
Electric
drive unit.
Teacher - Andreeva Leonella
Germanovna Electrical engineering helps to master disciplines. For specialty 140613 "Technical operation and
maintenance of electrical and electromechanical
equipment":
Power supply
Automation
Teacher - Myasnikova Tatiana
Vyacheslavovna Electrical engineering helps to master disciplines. For specialty 140613 "Technical operation and
maintenance of electrical and electromechanical
equipment":
Technical
exploitation
electrical and
electromechanical equipment;
Trial
reliability,
Adjustment of electrical and electromechanical
equipment;
Lecturer - Andrey Zakharov
Mikhailovich Electrical engineering helps to master disciplines. For specialty 140613 "Technical operation and
maintenance of electrical and electromechanical
equipment":
Structural processing technology
devices;
Control devices
Teacher - Grigorieva Svetlana
Valerievna
Contents The concept of electric current Physical quantities Distribution of electricity Ohm's law Degree IP Degree IK
The concept of electric current Electric current is the directed movement of electrically charged particles. Is it electric current?
The concept of electric current How to create a directed movement of charged particles? To maintain an electric current in a conductor, an external source of energy is needed, which would constantly maintain the potential difference at the ends of this conductor. Such energy sources are the so-called sources of electric current, which have a certain electromotive force (EMF), which creates and maintains a potential difference at the ends of the conductor for a long time.
The concept of electric current Is it possible for charged particles to move in all substances? Conductor Semiconductor. A dielectric is a body that contains a sufficient amount of free electric charges that can move under the influence of an electric field; this is a body that does not contain free electric charges inside. in insulators electricity impossible metals, solutions of salts and acids, moist soil, bodies of people and animals glass, plastic, rubber, cardboard, air is a material that conducts current, only when certain conditions silicon and alloys based on it
The concept of electric current Direct current (DC) Direct current is an electric current that does not change in time in direction. DC sources are galvanic cells, batteries and DC generators. Alternating current (AC) AC is called an electric current, the magnitude and direction of which change with time. The scope of alternating current is much wider than direct current. This is because the AC voltage can be easily stepped up or down with a transformer, almost anywhere. Alternating current is easier to transport over long distances.
Physical quantities Voltage Current Resistance Frequency Active power Reactive power Apparent power
Voltage (U) between two points is the potential difference at various points in an electrical circuit, which determines the presence of an electric current in it. Unit of measure - Volt (V) 1 V \u003d 1 J / C
Current strength (I) - a value equal to the ratio of the charge q passed through the cross section of the conductor to the time interval t during which the current flowed. Unit of measure - Ampere (A)
Resistance (R) is a physical quantity that characterizes the properties of a conductor to prevent the passage of electric current and is equal to the ratio of the voltage at the ends of the conductor to the strength of the current flowing through it. Unit of measure - Ohm (Ohm)
Frequency (f) - determines the number of current oscillations per second. Unit - Hertz (Hz) 50 Hz
Power Electrical power is a physical quantity that characterizes the rate of transmission or conversion of electrical energy. W VAR VA Q = U ∙ I ∙ sin φ P = U ∙ I ∙ cos φ S=U ∙ I
Power distribution Line voltage (U l) is the voltage between two phase wires (380 V) Phase voltage (U f) is the voltage between the neutral wire and one of the phase wires (220 V)
Ohm's Law: A physical law that defines the relationship between a source's Electromotive Force or voltage with current and conductor resistance. Experimentally installed in 1826, and named after its discoverer Georg Ohm. The essence of the law is simple: the current generated by the voltage is inversely proportional to the resistance that it has to overcome, and is directly proportional to the generating voltage. Ohm's law formula for a chain section: I \u003d U R
Diagram to help remember Ohm's law. You need to close the desired value, and the other two characters will give a formula for calculating it. Ohm's law
IP and IK Degree of protection IP consisting of two letters followed by two numbers. The IP code indicates the degree of protection against contact with conductive parts, the ingress of foreign solids, as well as liquids. The degree of protection IK consists of two letters followed by two numbers. The IK code indicates the degree of protection against external mechanical shocks.
IP Grade 1. Ingress protection of solid objects larger than 50mm (Example: accidental contact with hand) 2. Ingress protection of solid objects larger than 12mm (Example: contact with fingers) 3. Ingress protection of solid objects larger than 2.5mm (Example: contact with tools, wires) 4. Protection against ingress of solid objects larger than 1mm (Example: contact with small tools, thin wires) 5. Dust-proof (harmless to years) 6. Completely dustproof0. No protection
IP rating 1. Protection against vertically falling drops of water (condensation) 2. Protection against drops of water falling at a vertical angle up to 15° 3. Protection against water spray at a vertical angle up to 60° 4. Protection against water spray from any direction 5. Protection against low-pressure water jets from all directions 6. Protection against powerful water jets and waves 7. Protection against liquid penetration during temporary immersion 8. Protection against liquid penetration during long-term m pressure immersion 0. No protection
Grade IK 01 - Impact energy 0.150 J 02 - Impact energy 0.200 J 03 - Impact energy 0.350 J 04 - Impact energy 0.500 J 05 - Impact energy 0.700 J 06 - Impact energy 1.00 J 07 - Impact energy 2, 00 J 08 - Impact energy 5.00 J 09 - Impact energy 10.00 J 10 - Impact energy 20.00 J
Electrical (electromagnetic) energy is one of the types of energies at the disposal of man. Energy is the measure various forms the movement of matter and the transition of the movement of matter from one type to another. The advantages of electrical energy include: - relative ease of production, - the possibility of almost instantaneous transmission over great distances, - simple methods for converting into other types of energy (mechanical, chemical), - ease of control of electrical installations, - high efficiency of electrical devices.
To mine 1 ton of coal or ore, it is necessary to spend about 20 kWh of electricity, and to enrich the ore to 1 ton of ferrous concentrate, about 90 kWh is needed, to smelt 1 ton of electric steel, about 2000 kWh. Such large enterprise KMA as Lebedinsky GOK consumes about kWh of electricity per month for its work 1960 1970 1980 1990 2000 2005 Total generated (billion kWh) 30, TPP, %,2 HPP, %39.91214.2 NPP, %00.115.6 stations in Russia (RSFSR).
The prehistory of electrical engineering should be considered the period up to the 17th century. During these times, some electrical (attracting dust particles to amber) and magnetic phenomena (compass in navigation) were discovered, but the nature of these phenomena remained unknown. The 17th century should be considered the first stage in the history of electrical engineering, when the first studies in the field of electrical and magnetic phenomena appeared. On the basis of these studies, in 1799, the first source of electric current was created by Alessandro Volt (Alessandro Giuseppe Antonio Anastasio Volta) (Italian) - "voltaic column" This source is now called a galvanic cell in honor of Luigi Galvani (Italian), who did not live to see this discovery for one year, but being a doctor, did a lot to accomplish this discovery
The second stage in the development of electrical engineering d. – The magnetic action of current was discovered (Hans Christian Oersted) (Dutch) – Danish physicist d. – The law of interaction of electric currents was discovered (Andre-Marie Ampère) (French) – French physicist d. – The fundamental law of the electric circuit was discovered (Georg Simon Ohm) (German) – German physicist d. – The law of electromagnetic induction was discovered (Michael Faraday) (Eng.) – English physicist d. – Discovered about the phenomenon of self-induction (Joseph Henry) (Amer.) - American physicist d. - Manufacturing of a DC electric generator (Hippolyte Pixie) (French) - French toolmaker (by order of André-Marie Ampère (French) - French physicist.
The second stage of the development of electrical engineering in the city - A rule is formulated that determines the direction induction current(Emily Khristianovich (Heinrich Friedrich Emil) Lenz) (German) - Russian physicist g. - Invention of the first electric motor suitable for practical purposes (Boris Semenovich (Moritz Hermann von) Jacobi) (German) - Russian physicist - 1842 - Definition thermal action current (James Prescott Joule) (English) - English physicist, (Heinrich Friedrich Emil) Lenz) (German) - Russian physicist d. - Formulated rules for calculating circuits (Gustav Robert Kirchhoff) (German) - German physicist.
The third stage in the development of electrical engineering d. - The theory of the electromagnetic field was created (James Clerk (Clark) Maxwell) (English) - English physicist d. - Creation of the first electric generator that received practical application (Zenob (Zinovy) Theophilus Gramme) (Belgian) - French physicist d. - Invention of an electric incandescent lamp (obtaining a patent) (Alexander Nikolaevich Lodygin) (rus.) - Russian electrical engineer - Invention of the telephone (obtaining a patent) (Alexander Graham Bell) (English) - American physicist.
The third stage in the development of electrical engineering d. - Creation of a transformer for supplying current to lighting sources (obtaining a patent) (Pavel Nikolayevich Yablochkov) (rus.) - Russian electrical engineer d. - Construction of the first power line (Marcel Despres) (French) - French physicist d. - Invention of a radio receiver (Alexander Stepanovich Popov) (rus.) - Russian electrical engineer d. - Invention of a radiotelegraph (Guglielmo Marc oni) (Italian) Italian radio engineer g. - Electron discovered (Sir Joseph John Thomson) (English) - English physicist.
The fourth stage in the development of electrical engineering d. - Invention of the tube diode (Sir John Ambrose Fleming) (English) - English physicist d. - Invention of the tube triode (Lee de Forest) (English) - American physicist d. - Invention of the field-effect transistor (obtaining a patent) (Julius Edgar Lilienfeld) Austro-Hungarian physicist d. - Invention of the bipolar transistor (Wiel yam Shockley, John Bardeen and Walter Brattain at Bell Labs) American physicists d. - Invention of the integrated circuit. (Jack Kilby (Texas Instruments) based on germanium, Robert Noyce (founder of Fairchild Semiconductor) based on silicon) American inventors.
Electrical engineering is the science of practical application electrical and magnetic phenomena. Electron from Greek. electron - resin, amber. All basic definitions related to electrical engineering are described in GOST R. Constant values are denoted in capital letters: I, U, E, time-varying values of quantities are written in lowercase letters: i, u, e. An elementary electric charge is a property of an electron or proton that characterizes their relationship with their own electric field and interaction with an external electric field, which is determined for an electron and a proton by equal numerical values with opposite signs. Conventionally, a negative sign is attributed to the charge of the electron, and a positive sign to the charge of the proton. (-1.6* C)
An electromagnetic field is a type of matter determined at all points by two vector quantities that characterize its two sides, called "electric field" and "magnetic field", which has a force effect on electrically charged particles, depending on their speed and electric charge. The electric field is one of the two sides of the electromagnetic field, characterized by the impact on an electrically charged particle with a force proportional to the charge of this particle and independent of its speed. Magnetic field - one of the two sides of the electromagnetic field, characterized by the impact on a moving electrically charged particle with a force proportional to the charge of this particle and its speed.
A carrier of electric charges is a particle containing an unequal number of elementary electric charges of different signs. Electric current is a phenomenon of directed movement of electric charge carriers and (or) a phenomenon of changes in the electric field over time, accompanied by a magnetic field. In metals, charge carriers are electrons, in electrolytes and plasmas, ions. The value of the electric current through some surface S in this moment time is equal to the limit of the ratio of the electric charge q transferred by charged particles through the surface during the time interval t, to the duration of this interval, when the latter tends to zero, i.e. where i - electric current, (A); q is the charge, (C); t is time (s).
Direct current - a current at which the same charge is transferred during each identical period of time, i.e.: where I - electric current, (A); q is the charge, (C); t is time (s). The electric current strength is a vector quantity that characterizes the electric field and determines the force acting on an electrically charged particle from the electric field. It is equal to the ratio of the force acting on a charged particle to its charge and has the direction of the force acting on a particle with a positive charge. It is measured in N/C or V/m. Extraneous force - a force acting on an electrically charged particle, due to non-electromagnetic processes in macroscopic consideration. Examples of such processes are chemical reactions, thermal processes, the impact of mechanical forces, contact phenomena.
Electromotive force; EMF is a scalar quantity that characterizes the ability of an external field and an induced electric field to cause an electric current. Numerically, the EMF is equal to the work A (J) performed by these fields when transferring a unit charge q (C) equal to 1 C. where E - (EMF) electromotive force, V; A is the work of external forces when moving the charge (J); q is the charge, (C). Electrical voltage is a scalar value equal to the linear integral of the electric field strength along the considered path. It is determined for electric voltage U 12 along the considered path from point 1 to point 2 voltage is the work of field forces with strength ε, spent on the transfer of a unit charge (1 C) along the path l. The potential difference is the electric voltage in an irrotational electric field, which characterizes the independence of the choice of the integration path.
Electric circuit - a set of devices and objects that form a path for electric current, electromagnetic processes in which can be described using the concepts of electromotive force, electric current and electric voltage. The simplest electrical circuit (wiring diagram).
Electrical circuit element - a separate device that is part of the electrical circuit, performing in it certain function. The main elements of the simplest electrical circuit are sources and receivers of electrical energy. The simplest electrical circuit (wiring diagram).
In sources of electrical energy, various types of energy, such as chemical, mechanical, are converted into electrical (electromagnetic). In receivers of electrical energy, the reverse transformation occurs - electromagnetic energy is converted into other types of energy, for example, chemical (galvanic baths for aluminum smelting or protective coating), mechanical (electric motors), thermal (heating elements), light (fluorescent lamps). Sources of electrical energy Receivers of electrical energy Conductors
Electrical circuit diagram - a graphical representation of an electrical circuit containing conventions its elements and showing the connection of these elements. To collect circuits, circuit diagrams are used, where each element corresponds to a conventional graphic and letter designation, and for circuit calculations, equivalent circuits are used, in which real elements are replaced by calculation models, and all auxiliary elements are excluded. Schematic diagrams are drawn up in accordance with GOST, for example: GOST one system design documentation. Conditional graphic designations in schemes. Inductors, chokes, transformers, autotransformers and magnetic amplifiers GOST Unified system for design documentation. Conditional graphic designations in schemes. Resistors, capacitors
Equivalent circuit - a diagram of an electrical circuit that displays the properties of the circuit under certain conditions. An ideal element (of an electric circuit) is an abstract representation of an element of an electric circuit, characterized by one parameter. An electrical circuit outlet is a point in an electrical circuit intended to be connected to another electrical circuit. A two-terminal network is a part of an electrical circuit with two dedicated terminals. Chains are simple and complex. In simple circuits, all elements are connected in series. In complex circuits, there are branches for current.
According to the type of current, the circuits are divided into direct, variable and alternating current circuits. Direct current - an electric current that does not change in time t (Fig. 1.3.a). All other currents are time-varying (Fig. 1.3.b.) or variable (Fig. 1.3.c.). An alternating current circuit is a circuit with a current that varies according to a sinusoidal law. I t I t t I a) b) c) Fig Types of currents in circuits.
Linear circuits include circuits in which the electrical resistance of each section does not depend on the value and direction of current and voltage. Those. the current-voltage characteristic (CVC) of the circuit sections is presented as a straight line (linear dependence) (Fig. a). a) b) Fig. Volt - ampere characteristics (CVC) of circuits. U I U I where U - voltage, (V); I - current strength, (A). The remaining circuits are called non-linear (Fig. 1.3.b).
The electrical resistance to direct current is a scalar value equal to the ratio of the constant electrical voltage between the terminals of a passive two-terminal network to the direct electrical current in it. where R is the electrical resistance to direct current, (Ohm); ρ - specific resistance, (Ohm*m); - conductor length, (m); S is the cross-sectional area, (m 2), where R is the electrical resistance to direct current, (Ohm); U - voltage, (V); I - current strength, (A). Resistor - an element of an electrical circuit designed to use its electrical resistance. For wires, the resistance is found by the formula:
The resistance of wires, resistors and other conductors of electric current depends on the temperature T environment Electrical conductivity (for direct current) is a scalar value equal to the ratio of direct electric current through a passive two-terminal network to a constant electrical voltage between the terminals of this two-terminal network. Those. the reciprocal of the resistance where R is the electrical resistance to direct current, (Ohm); R 20 - electrical resistance to direct current at a temperature of 20ºС, (Ohm); α - temperature coefficient of resistance, depending on the material; T is the ambient temperature, (ºС). where G - electrical conductivity, (Cm) (Siemens) or Ohm -1; U - voltage, (V); I - current strength, (A); R - electrical resistance, (Ohm).
Flux linkage is the sum of magnetic fluxes linked to the elements of the circuit of an electric circuit. Flux linkage of self-induction - flux linkage of an element of an electrical circuit, due to electric current in this element. Intrinsic inductance is a scalar value equal to the ratio of the flux linkage of the self-induction of an electrical circuit element to the electric current in it. where Ψ is the flux linkage, (Wb); m is the number of turns; Ф – magnetic flux (Wb). where L - inductance, (H); Ψ – flux linkage, (Wb); I - current strength, (A).
An inductive coil is an element of an electrical circuit designed to use its own inductance and (or) its magnetic field. The voltage at the terminals of the coil is equal to the product of the inductance and the rate of change of current through it. where u L is voltage, (V); L - inductance, (H); i - current strength, (A). The current through the coil is directly proportional to the integral of the voltage and inversely proportional to the inductance of the coil. where i L is the current strength, (A); L - inductance, (H); u - voltage, (V).
The inductance of a single-layer solid wound coil can be determined by the empirical formula: Inductance of a multilayer coil: where L is the inductance, (uH); D is the coil diameter, (cm); ω is the number of coil turns; - winding length, (cm); t is the thickness of the winding, (cm).
The electrical capacitance of a conductor is a scalar quantity that characterizes the ability of a conductor to accumulate an electric charge, equal to the ratio of the electric charge of the conductor to its electric potential, assuming that all other conductors are at infinity and that the electric potential of an infinitely distant point is taken equal to zero. The electrical capacitance between two conductors is a scalar value equal to the absolute value of the ratio of the electric charge of one conductor to the difference in the electric potentials of two conductors, provided that these conductors have the same charge, but opposite in sign, and that all other conductors are at infinity. where C is the capacitance, (F); q - charge, (C); Uc is the voltage between the terminals of the capacitor, (V).
The electric capacitance of a capacitor is the electric capacitance between the electrodes of an electric capacitor. For a flat capacitor with two plates (plates), the capacitance is: where C is the capacitance, (pF); S is the area of the capacitor plates, (cm2); d is the distance between the capacitor plates (dielectric width), (cm); ε is the permittivity of the dielectric (vacuum and air = 1; amber = 2.8; dry pine = 3.5; marble = 8-10; ferroelectric ceramics =). An electrical capacitor is an element of an electrical circuit designed to use its electrical capacitance.
Where u С is voltage, (V); C - capacity, (F); i - current strength, (A). The equivalent current through a capacitor is directly proportional to the capacitance of the capacitor and the rate of change of voltage across its plates. where C - capacity, (F); i C - current strength, (A). u is voltage, (V). The voltage at the terminals of the capacitor will change in direct proportion to the integral over the current and inversely proportional to the capacitance of the capacitor.
A section of an electric circuit is a part of an electric circuit containing a selected set of its elements. A branch of an electrical circuit is a section of an electrical circuit along which the same electric current flows ( section a-b, b-d, b-d). Knot electrical network- the junction of the branches of the electrical circuit (a, b, c, c, d, d). The circuit of an electrical circuit is a sequence of branches of an electrical circuit that forms a closed path, in which one of the nodes is both the beginning and end of the path, and the rest meet only once ( section a-b-d-c-a). E1E1 R2 R3 E2E2 R4 R5 E4 R7 ab c d R6 c d R1
Each device in the electrical circuit can correspond to several equivalent circuits. The type and parameters of the circuit depend on the features of many factors, for example, on the design of the device, operating mode, frequency of the acting signal, the required accuracy of calculations, the assumptions made
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DC circuits
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Electrical engineering is the science of electrical phenomena, the production, transmission, distribution, transformation and use of electrical energy. The rapid development of electrical engineering is explained by the fact that electrical energy has a number of significant advantages compared to other types of energy. 1. Electrical energy is easily converted into other types of energy - thermal, mechanical, chemical (and vice versa). 2. Electrical energy can be easily transmitted through wires over long distances. 3. Electric energy is easy to bring to the consumer and spend in any quantity. 4. The efficiency of electrical installations is much higher than the efficiency of installations powered by other energy sources.
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The purpose of studying the discipline is to provide fundamental knowledge for the development of special disciplines and practical work when operating electrical devices in automotive technology. The objectives of the discipline are: the study of the basic laws of electrical engineering, the formation of the trainees' concepts of the theory of electrical circuits; study of the structure of electrical machines and electronic devices; mastering the methods of theoretical analysis and experimental study of electromagnetic processes; formation of ideas about the structure and principles of operation of electrical equipment used in transport and technological machines.
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At present, the basic concepts of electrical engineering are defined by: current terminological standards and recommendations of the International Electrotechnical Commission (IEC), International Electrotechnical Dictionary (IEC, 2nd edition, 1954, French and English); interstate standard GOST 19880 - 74 "Electrical engineering. Basic concepts. Terms and definitions"; Russian standard GOST R 52002 - 2003 “Electrical engineering. Terms and definitions of basic concepts.
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Table 1 - Basic concepts and their designations
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Table 2 - Multipliers and prefixes for the formation of decimal multiples and submultiples
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Table 3 - Some units of mechanical quantities in the SI system
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Table 4 - Some units of electrical quantities in the SI system
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Table 5 - Some units of magnetic quantities in the SI system
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Any electrical circuit contains sources of electrical energy, receivers (electrical loads), switching equipment, connecting lines and measuring instruments.
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Sources of electrical energy are electrical generators, in which mechanical energy is converted into electrical or primary cells and batteries, in which chemical, thermal, light and other types of energy are converted into electrical energy. Consumers of electrical energy include electric motors, heating and lighting devices, etc. An electrical circuit is a graphical representation of an electrical circuit. The equivalent circuit of an electric circuit consists of a set of various idealized elements chosen so that it is possible to describe the processes in the circuit with a given or necessary approximation.
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Conditionally - graphic designations in accordance with ESKD
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The circuit equivalent circuit configuration is determined by the following geometric (topological) concepts: branch, node, contour. A circuit branch consists of one or more series-connected elements, each of which has two outputs (beginning and end), and the beginning of the next is attached to the end of each previous element. Three or more branches are connected at a circuit node. A contour is a closed path passing through several branches so that no branch and no node occurs more than once. All consumers of electrical energy are usually characterized by some parameters.
Lecture contentFormalities
Course Overview
Introduction to theoretical electrical engineering:
TOE is not difficult!
Basic definitions
Ohm's and Kirchhoff's laws
Classification of electrical circuits
Brief conclusions
2
formalities
Lecturer:Degtyarev Sergey Andreevich
Final examination:
Exam
Classes:
Lectures
Practice (the results are ranked)
Reporting during the semester:
The rating is submitted to the dean's office 3 times per semester
(in October, in November, at the end of the semester)
Missing two or more classes in a row - memo to the dean's office
Homework is due at the next practice session.
3
Formalities (continued)
Types of intermediate control:Independent work - usually possible
use notes, study guides, etc.
Examinations - 3 works per semester; it is forbidden
use any reference materials;
unwritten control submitted to the exam
Homework - assigned to each
practical lesson, be sure to pass on
next practice session
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Rating
Main indicators for rating calculationAverage score
Percentage of completion of the curriculum (percentage
completed work - home, independent,
control)
Rating = (average score) x (percentage of completion)
Attendance
Ranking can affect the exam
appraisal in disputed cases
5
Bibliography
Main literature:Additional
literature:
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Fundamentals of theoretical electrical engineering: Tutorial/ Yu. A.
Bychkov, V. M. Zolotnitsky, E. P. Chernyshev, A. N. Belyanin - St. Petersburg:
Publishing house "Lan", 2009.
Collection of tasks on the basics of theoretical electrical engineering:
Tutorial / Under. ed. Yu. A. Bychkov, V. M. Zolotnitsky,
E. P. Chernysheva, A. N. Belyanina, E. B. Solovieva. - St. Petersburg:
Publishing house "Lan", 2011.
Fundamentals of Circuit Theory: Laboratory Workshop on
theoretical electrical engineering / Ed. Yu. A. Bychkova, E. B.
Solovieva, E. P. Chernysheva. St. Petersburg: Publishing House of St. Petersburg Electrotechnical University "LETI",
2012.
Handbook of the Fundamentals of Theoretical Electrical Engineering: Educational
allowance / Under. ed. Yu. A. Bychkov, V. M. Zolotnitsky, E. B.
Solovieva, E. P. Chernysheva. - St. Petersburg: Publishing house "Lan", 2012.
Savelyev I.V. Course of general physics. Book 2. Electricity and
magnetism
Beletsky A.F. Theory of linear electrical circuits
K. Tietze, W. Schenk Semiconductor circuitry
Horowitz P., Hill W. - The Art of Circuitry
Open Course 6.002 OCW MIT – http://ocw.mit.edu
Course Overview
The main topics of the course on the theoretical foundations of electrical engineering (1semester):
Calculation of resistive electrical circuits (circuitry)
Calculation of linear dynamic circuits (circuitry, theory
management)
Numerical calculation methods (computer processing
signals)
Calculation of linear dynamic circuits with sinusoidal
influences (circuitry, power supply circuits)
Operator method for calculating circuits - Laplace transform
(control theory)
Frequency characteristics (radio engineering, audio engineering, TV)
Calculation of three-phase circuits (power supply circuits)
Inductively coupled circuits (transformer technology,
power supply schemes)
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Course Overview
The main topics of the course of the theoretical foundations of electrical engineering(2 semester):
Spectral methods for calculating circuits (radio engineering,
television, audiovisual equipment)
Active circuits and operational amplifiers
(circuitry, digital technology)
Long lines - chains with distributed parameters
(microwave devices and antennas)
Discrete systems (digital signal processing,
computer vision, digital devices And
microprocessors, systems on a chip, medical
technique)
Nonlinear systems (circuitry, audiovisual
technology, radio engineering)
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Example
incandescent lampTask: to simulate the behavior of an incandescent lamp in
electrical circuit
*image source: http://jeromeabel.net
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Example (continued)
Connect the lamp to a voltage source*image sources: http://jeromeabel.net, https://openclipart.org
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Example (continued)
TargetBuild an object model suitable for
predicting its behavior with sufficient accuracy
Means to achieve the goal:
Consider only properties of interest to us and
object parameters (abstraction)
Use the most simple methods, accuracy
which are still enough to solve the problem (simplification
and idealization)
Apply well-known mathematical methods to
building and using the model
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Example (continued)
What current will flow through the light bulb?How long will the light bulb last on one battery?
What size wire should be chosen for connection?
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