2017-10-25
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An electric circuit is simply an interconnection of the elements. an element is the basic building block of a circuit.Circuit analysis is the process of determining voltages across (or the currents through) the elements of the circuit. There are two types of elements found in electric circuits: passive elements and active elements. An active element is capable of generating energy while a passive element is not. Examples of passive elements are resistors, capacitors, and inductors. Typical active elements include generators, batteries, and operational amplifiers. The most important active elements are voltage or current sources that generally deliver power to the circuit connected to them. There are two kinds of sources: independent and dependent sources.
An ideal independent source is an active element that provides a specified voltage or current that is completely independent of other circuit elements. In other words, an ideal independent voltage source delivers to the circuit whatever current is necessary to maintain its terminal voltage. Physical sources such as batteries and generators may be regarded as approximations to ideal voltage sources. Similarly, an ideal independent current source is an active element that provides a specified current completely independent of the voltage across the source. That is, the current source delivers to the circuit whatever voltage is necessary to maintain the designated current.
An ideal dependent (or controlled) source is an active element in which the source quantity is controlled by another voltage or current.
Since the control of the dependent source is achieved by a voltage or current of some other element in the circuit, and the source can be voltage or current, it follows that there are four possible types of dependent sources, namely:
1. A voltage-controlled voltage source (VCVS).
2. A current-controlled voltage source (CCVS).
3. A voltage-controlled current source (VCCS).
4. A current-controlled current source (CCCS).
Dependent sources are useful in modeling elements such as transistors, operational amplifiers, and integrated circuits. It should be noted that an ideal voltage source (dependent or independent) will produce any current required to ensure that the terminal voltage is as stated, whereas an ideal current source will produce the necessary voltage to ensure the stated current flow. Thus, an ideal source could in theory supply an infinite amount of energy. It should also be noted that not only do sources supply power to a circuit, they can absorb power from a circuit too. For a voltage source, we know the voltage but not the current supplied or drawn by it. By the same token, we know the current supplied by a current source but not the voltage across it.
Задание на СРСП: решение задач по вариантам: топологические характеристики..
Основная литература:
1. ПрянишниковВ.А. Теоретические основы электротехники. Курс лекций. С-Петербург, Корона. Принт, 2004. – с. 24-30, 62-110.
Дополнительная литература:
2. Алехин В.А. Электротехника. Мультимедийный курс лекций с использованием компьютерного моделирования. Москва, МИРЭА, 2016. - с. 4-20.
