Electrical engineering is a field of science and technology studies the electrical and magnetic phenomena and their use in practical purposes of production, transformation, transmission and consumption of electric energy.
Electronics is the area of science and technology, studying electrical and magnetic phenomena and their use in practical purposes of production, transformation, transmission and consumption of information.
Each science has its own terminology. Memorize the terms, concepts of electrical engineering and electronics.
The circuit is a collection of devices intended for production, transmission, transformation and use of electric current.
All electrical devices on purpose, principle of action and constructive design can be divided into three large groups.
Sources of energy, i.e. devices that produce electric current (generators, thermocouples, solar cells, chemical elements).
The electromotive force of an electrical potential difference created as a source of electrical energy (electrochemical element, mechanical generator, thermocouple, solar cell and other).
Receivers, or load, i.e. devices that consume electric current (electric motors, electric lamps, electrical machinery etc).
Conductors, and also different kinds of commuting equipment (circuit breakers, relays, contactors etc).
Directed motion of electric charges is called an electric current. Electric current can appear in a closed circuit. The electric current, the direction and magnitude of which are unalterable, called DC and represent a capital letter I.
The electric current, the magnitude and direction which are not constant, is called alternating current. Value of alternating current at a given moment of time is called instant and represent a lowercase letter i.
For electrical circuit must be the availability of energy sources. In any source by external forces of non-electrical origin is created electromotive force. The source terminals there is a potential difference or voltage, which is under the influence of external connected to the supply of the chain, there is an electric current.
Distinguish between active and passive circuit areas and elements of chains. Active called electrical circuits containing sources of energy, passive electrical circuits, not containing sources of energy.
Linear circuit is such a circuit in which no option chain does not depend on the size or direction of the current or voltage.
Nonlinear circuit is such circuit, which contains at least one non-linear element. Parameters of nonlinear elements depend on the magnitude or direction of the current or voltage.The simplest passive elements of the scheme of substitution are the resistance, inductance, and capacitance.
In a real circuit electric resistance have not only a rheostat or resistor, but wires, coils, capacitors etc. A common characteristic of all devices with resistance, is irreversible transformation of electric energy into thermal energy. Thermal energy is released in the resistance, is used or scattered in space. In the scheme of substitution in all cases when it is necessary to take into account the irreversible transformation of energy is included resistance.