Electromagnetism

Electricity · Magnetism

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An electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources, and switches. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. The concept of electrical elements is used in the analysis of Electrical networks. |- align = "center"| |width = "25"| | |- align = "center"| || Potentiometer |- align = "center"| | | |- align = "center"| Resistor| | An inductor is a passive electrical component designed to provide Inductance in a circuit A capacitor is a passive electrical component that can store Energy in the Electric field between a pair of conductors A transmission line is the material medium or structure that forms all or part of a path from one place to another for directing the transmission of energy A voltage source is any device or system that produces an Electromotive force between its terminals OR derives a secondary voltage from a primary A current source is an electrical or electronic device that delivers or absorbs electric current A switch is a mechanical device used to connect and disconnect an electric Circuit at will

An electrical circuit is a network that has a closed loop, giving a return path for the current. A network is a connection of two or more components, and may not necessarily be a circuit.

Electrical networks that consist only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines) can be analyzed by algebraic and transform methods to determine DC response, AC response, and transient response. Direct current ( DC) is the unidirectional flow of Electric charge. An alternating current ( AC) is an Electric current whose direction reverses cyclically as opposed to Direct current, whose direction remains constant In Electrical engineering and Mechanical Engineering, a transient response or natural response is the response of a system to a change from equilibrium

A network that also contains active electronic components is known as an electronic circuit. Passivity is a property of engineering systems most commonly used in electronic engineering and control systems Electronics refers to the flow of charge (moving Electrons through Nonmetal conductors (mainly Semiconductors, whereas electrical An electronic circuit is a closed path formed by the interconnection of Electronic components through which an Electric current can flow Such networks are generally nonlinear and require more complex design and analysis tools.

Contents 1 Design methods 2 Electrical laws 3 Network simulation software 3.1 Linearization around operating point 3.2 Piecewise-linear approximation 4 See also

Design methods

To design any electrical circuit, either analog or digital, electrical engineers need to be able to predict the voltages and currents at all places within the circuit. Analogue electronics (or analog in American English) are those electronic systems with a continuously Variable signal Digital electronics are Electronics systems that use Digital signals Digital electronics are representations of Boolean algebra also see Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of Engineering that deals with the study and application of Linear circuits, that is, circuits with the same input and output frequency, can be analyzed by hand using complex number theory. A linear circuit is an Electric circuit in which for a sinusoidal input voltage of Frequency f, any output of the circuit (current through any Complex plane In Mathematics, the complex numbers are an extension of the Real numbers obtained by adjoining an Imaginary unit, denoted Other circuits can only be analyzed with specialized software programs or estimation techniques. Computer programs (also software programs, or just programs) are instructions for a Computer.

Circuit simulation software, such as VHDL and HSPICE, allows engineers to design circuits without the time, cost and risk of error involved in building circuit prototypes. A spice is a dried Seed, Fruit, Root, Bark or vegetative substance used in Nutritionally insignificant quantities as a Food additive

Electrical laws

A number of electrical laws apply to all electrical networks. These include

• Kirchhoff's current law: The sum of all currents entering a node is equal to the sum of all currents leaving the node. For other laws named after Gustav Kirchhoff, see Kirchhoff's laws.
• Kirchhoff's voltage law: The directed sum of the electrical potential differences around a loop must be zero. For other laws named after Gustav Kirchhoff, see Kirchhoff's laws.
• Ohm's law: The voltage across a resistor is equal to the product of the resistance and the current flowing through it (at constant temperature). Ohm's law applies to Electrical circuits it states that the current through a conductor between two points is directly proportional to the
• Norton's theorem: Any network of voltage and/or current sources and resistors is electrically equivalent to an ideal current source in parallel with a single resistor. Norton's theorem for Electrical networks states that any collection of Voltage sources Current sources and Resistors with two terminals is
• Thévenin's theorem: Any network of voltage and/or current sources and resistors is electrically equivalent to a single voltage source in series with a single resistor. In electrical circuit theory, Thévenin's theorem for linear Electrical networks states that any combination of Voltage sources Current sources

• See also Analysis of resistive circuits. A network in the context of Electronics, is a collection of interconnected components

Other more complex laws may be needed if the network contains nonlinear or reactive components. Non-linear self-regenerative heterodyning systems can be approximated. In Radio and Signal processing, heterodyning is the generation of new frequencies by mixing or multiplying two Oscillating waveforms Applying these laws results in a set of simultaneous equations that can be solved either by hand or by a computer. In Mathematics simultaneous equations are a set of Equations containing multiple variables

Network simulation software

More complex circuits can be analyzed numerically with software such as SPICE or symbolically using software such as SapWin. A spice is a dried Seed, Fruit, Root, Bark or vegetative substance used in Nutritionally insignificant quantities as a Food additive SAPWIN (Symbolic Analysis Program for Windows is a symbolic circuit simulator written in C++ for the Windows (95/98/ME/NT/2000 environment

Linearization around operating point

When faced with a new circuit, the software first tries to find a steady state solution, that is, one where all nodes conform to Kirchhoff's Current Law and the voltages across and through each element of the circuit conform to the voltage/current equations governing that element. Steady state is a more general situation than Dynamic equilibrium.

Once the steady state solution is found, the operating points of each element in the circuit are known. For a small signal analysis, every non-linear element can be linearized around its operation point to obtain the small-signal estimate of the voltages and currents. This is an application of Ohm's Law. The resulting linear circuit matrix can be solved with Gaussian elimination. In Linear algebra, Gaussian elimination is an efficient Algorithm for solving systems of linear equations, to find the rank of a matrix

Piecewise-linear approximation

Software such as the PLECS interface to Simulink uses piecewise-linear approximation of the equations governing the elements of a circuit. PLECS (Piece-wise Linear Electrical Circuit Simulation is a Simulink toolbox for system-level simulations of Electrical circuits developed by Plexim Simulink, developed by The MathWorks, is a commercial tool for modeling simulating and analyzing multidomain dynamic systems Piecewise linear may refer to Piecewise linear function Piecewise linear manifold The circuit is treated 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.

See also

A network in the context of Electronics, is a collection of interconnected components An alternating current ( AC) is an Electric current whose direction reverses cyclically as opposed to Direct current, whose direction remains constant In a hybrid set Hybrid coil, or Resistance hybrid, balancing network is a circuit used to match i A bridge circuit is a type of Electrical circuit in which the current in a conductor splits into two parallel paths and then recombines into a single conductor Digital electronics are Electronics systems that use Digital signals Digital electronics are representations of Boolean algebra also see A circuit diagram (also known as an electrical diagram Wiring diagram, elementary diagram or electronic Schematic) is a simplified conventional pictorial representation Circuit theory is the theory of accomplishing work by means of routing matter through a loop. A diode bridge or bridge rectifier is an arrangement of four diodes in a bridge configuration that provides the same polarity of output Direct current ( DC) is the unidirectional flow of Electric charge. Biasing in Electronics is the method of establishing predetermined Voltages and/or Currents at various points of a circuit to set an appropriate In Electrical engineering, the term ground or earth has several meanings depending on the specific application areas The electronic&ndash hydraulic analogy (derisively referred to as the drain-pipe theory by Oliver Heaviside) is the most widely used analogy for "electron fluid" Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal Alternating current (AC If an electric circuit has a well-defined output terminal the circuit connected to this terminal (or its Input impedance) is the load. Mathematical methods are integral to the study of electronics. The word netlist can be used in several different contexts but perhaps the most popular is in the field of Electronic design. A network analyzer is an instrument used to analyze the properties of Electrical networks especially those properties associated with the reflection and transmission A resistor–capacitor circuit (RC circuit, or RC filter or RC network, is an Electric circuit composed of resistors and capacitors driven by An LC circuit is a variety of resonant circuit or tuned circuit and consists of an Inductor, represented by the letter L and a Capacitor, represented An RLC circuit (also known as a Resonant circuit tuned circuit or LCR circuit is an Electrical circuit consisting of a Resistor (R an In general the lumped component model is a way of simplifying the behaviour of spatially distributed systems into a Topology consisting of discrete entities that approximate The distributed element model or transmission line model of electrical circuits assumes that the attributes of the circuit ( resistance, Capacitance In Electronics, a voltage divider (also known as a potential divider) is a simple Linear circuit that produces an output Voltage ( A schematic is a diagram that represents the elements of a System using abstract graphic Symbols rather than realistic pictures If two or more circuit components are connected end to end like a daisy chain it is said they are connected in series. A spice is a dried Seed, Fruit, Root, Bark or vegetative substance used in Nutritionally insignificant quantities as a Food additive In Electronics, a continuity test is the checking of an Electric circuit to see if current flows (that it is in fact a complete circuit Voltage drop is the reduction in Voltage in an Electrical circuit between the source and load Mesh analysis (sometimes referred to as loop analysis or mesh current method) is a method that is used to solve planar circuits for the Voltage and

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