Circuit theory basic Elements,Nodes, Branches and Loops of a Circuit,Voltage and Current sources.
Elements – The term elements means "components and sources."
An electric circuit based on three concepts, namely, node, branch and loop. As per definition, an electric network is a combination of interconnected circuit elements. A network may or may not provide closed path to the electric current to flow. But, an electrical circuit may be a combination of one or more networks which gives closed path to the electric current. That means, when one or more networks are interconnected together to complete one or more paths to the current, an electric circuit is formed.
Nodes of Electric Circuit
The point through which an circuit element is connected to the circuit is called node. It is better to say, node is a point where, terminal of two or more circuit elements are connected together. Node is a junction point in the circuit.
nodes of electric circuit
he point through which an circuit element is connected to the circuit is called node. It is better to say, node is a point where, terminal of two or more circuit elements are connected together. Node is a junction point in the circuit.
Branch of Electric Circuit
The elements connected to an electric circuit is generally two terminal element. When, one circuit element is connected to the circuit, it connects itself through both of its terminals, to be a part of a closed path.
Loops in Electric Circuit
An electric circuit has numbers of nodes. If one starts from one node and after going through a set of nodes returns to same starting node without crossing any of the intermediate node twice, he has travels through one loop of the circuit.
Voltage Source and Current Source
A Source is a device which converts mechanical, chemical, thermal or some other form of energy into electrical energy. In other words, the source is an active network element meant for generating electrical energy. The various types of sources available in the electrical network are voltage source and current sources. A voltage source has a forcing function of emf whereas the current source has a forcing function of current.
The current and voltage sources are further categorised as an ideal source or practical source.
Voltage Source
A voltage source is a two-terminal device whose voltage at any instant of time is constant and is independent of the current drawn from it. Such a voltage source is called an Ideal Voltage Source and have zero internal resistance. Practically an ideal voltage source cannot be obtained.
Sources having some amount of internal resistances are known as Practical Voltage Source.due to this internal resistance; voltage drop takes place, and it causes the terminal voltage to reduce. The smaller is the internal resistance (r) of a voltage source, the more closer it is to an Ideal Source.
Current Source
The current sources are further categorised as Ideal and Practical current source.
An Ideal current source is a two-terminal circuit element which supplies the same current to any load resistance connected across its terminals.It is important to keep in mind that the current supplied by the current source is independent of the voltage of source terminals. It has infinite resistance.
A practical current source is represented as an ideal current source connected with the resistance in parallel.
Voltmeters
A voltmeter is an instrument that measures the difference in electrical potential between two points in an electric circuit. An analog voltmeter moves a pointer across a scale in proportion to the circuit’s voltage; a digital voltmeter provides a numerical display. Any measurement that can be converted to voltage can be displayed on a meter that is properly calibrated; such measurements include pressure, temperature, and flow.
Ammeters
An ammeter measures the electric current in a circuit. The name is derived from the name for the SI unit for electric current, amperes (A).
In order for an ammeter to measure a device’s current, it must be connected in series to that device. This is necessary because objects in series experience the same current. They must not be connected to a voltage source — ammeters are designed to work under a minimal burden, (which refers to the voltage drop across the ammeter, typically a small fraction of a volt).
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