# Electrical Network

Come, friends, today we will know about Electrical Network. An electrical network is the interconnection of electrical components (eg, batteries , resistors , inductors , capacitors , switches , transistors ,) or electrical elements consisting of a model of such interconnection (eg, voltage sources , Current sources , resistors , inductances , capacitances ) An electrical circuit is a network consisting of a closed loop, which gives a return path for current. linearElectrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linearly distributed elements (transmission lines), have the property that signals are linearly superimposable . . Thus they are more easily analyzed using powerful frequency domain methods such as the Laplace transform to determine the DC response , AC response and transient response .

A resistive circuit is a circuit that contains only resistors and ideal current and voltage sources. The analysis is complicated by the analysis of resistor circuits with less capacitor and inductor. If the sources are stationary ( DC ) sources, the result is a DC circuit . The effective resistance and current distribution properties of arbitrary resistive networks can be modeled in terms of their graph measures and geometric properties. 

A network consisting of active electronic components is known as an electronic circuit . Such networks are generally nonlinear and require more complex design and analysis tools.

## classification

### passively

An active network has at least one voltage source or current source that can supply energy to the network indefinitely. A passive network does not have an active source.

An active network consists of one or more sources of electromotive force . Practical examples of such sources include batteries or generators . Active elements can inject power to circuits, provide power gain and control current flow within the circuit.

In passive networks there is no source of electromotive force. These contain passive elements such as resistors and capacitors.

### linearly

A network is linear if its signals obey the principle of superposition ; Otherwise it is non-linear. Passive networks are generally considered to be linear, but there are exceptions. For example, an inductor with an iron core can be driven into saturation if operated with a large enough current . In this region, the behavior of the inductor is very non-linear.

## loosely

Discrete passive components (resistors, capacitors, and inductors) are called lumped elements because all of their, respectively, resistance, capacitance, and inductance are assumed to be located (“lumps”) in the same location. This design philosophy is called the lumped-element model and the network thus designed is called a lumped-element circuit . This is the traditional approach to circuit design. At high enough frequencies the knotty perception is no longer there because the component dimensions comprise a significant fraction of the wavelength . Such cases require a new design model called the distributed-element model . Networks designed for this model are called distributed-element circuits .

A distributed-element circuit consisting of a few lumped components is called a semi-lumped design. An example of a semi-lumped circuit is a combineline filter.

## classification of sources

Sources can be classified as independent sources and dependent sources.

### Independent

An ideal independent source maintains the same voltage or current regardless of the other elements present in the circuit. Its value is either constant (DC) or sinusoidal (AC). Any change in the connected network does not change the strength of the voltage or current.

### dependent

Dependent sources rely on a particular element of a circuit to deliver power or voltage or current depending on the type of source.

electrical law

Several electrical laws apply to all electrical networks. This includes:

Kirchhoff’s current law: The sum of all currents entering a node is equal to the sum of all currents leaving the node.

Kirchhoff’s Voltage Law: The directed sum of the electric potential difference around a loop must be zero.

Ohm’s Law: The voltage across a resistor is equal to the product of the resistance and the current flowing through it.

Norton’s Theorem: Any network of voltage or current sources and resistors is electrically equivalent to an ideal current source parallel to a single resistor.

Thevenin’s Theorem: Any network of voltage or current sources and resistors is electrically equivalent to a single voltage source in series with a single resistor.

Superposition Theorem: In a linear network with multiple independent sources, the response in a particular branch when all sources are acting together is equal to the linear sum of the individual responses calculated by taking one independent source at a time.

Other more complex laws may be needed if the network has non-linear or reactive components. Non-linear self-regenerative heterodimerization systems can be predicted. Applying these laws creates a set of isometric equations that can be solved algebraically or numerically.

## Design Methods

To know about Electrical Network, now we will know about Design Methods

To design any electrical circuit, either analog or digital, electrical engineers must be able to predict voltages and currents at all locations within the circuit. Simple linear circuits can be analyzed by hand using complex number theory. In more complex cases the circuit can be analyzed with specialized computer programs or inference techniques such as piecewise-linear models.

Circuit simulation software, such as HSPICE (an analog circuit simulator),  and languages ​​such as VHDL-AMS and Verilog-AMS allow engineers to design circuits without the time, cost, and risk of error involved in building circuit prototypes.

## network simulation software

More complex circuits can be analyzed numerically with software such as SPICE or GNUCAP, or symbolically using software such as SapWin.

### Linearization around the operating point

When faced with a new circuit, the software first attempts to find the steady state solution, that is, one where all nodes conform to Kirchhoff’s current law and the voltage across and through each element of the circuit is/are Elements corresponding to the equations governing the present.

Once the steady state solution is found, the operating points of each element in the circuit are known. For a small-signal analysis, each non-linear element can be linearized around its conducting point to obtain small-signal estimates of voltages and currents. This is an application of Ohm’s law. The resulting linear circuit matrix can be solved with Gaussian elimination.

### piece-linear approximation

The interface for software such as PLECS Simulink uses piecewise linear approximations of the equations governing the elements of a circuit. The circuit is considered as a completely linear network of ideal diodes. Every time a diode switches from ON to OFF or vice versa, the configuration of the linear network changes. Adding more detail to the approximation of equations increases the accuracy of the simulation, but also increases its running time.