Electrical network
Encyclopedia : E : EL : ELE : Electrical network
An electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, and switches. It can be as large as an electricity distribution or transmission network.
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 simple circuit elements, and may not necessarily be a circuit.
Design aims
In the case of power distribution networks, engineers design the circuit to transport the energy as efficiently as possible, while at the same time taking into account economic factors, network safety and redundancy. These networks use components such as power lines, cables, circuit breakers, switches and transformers.Design methods
To design any electrical circuits, electrical engineers need to be able to predict the voltages and currents in the circuit. Linear circuits can be analysed to a certain extent by hand because complex number theory gives engineers the ability to treat all linear elements using a single mathematical representation.Many engineers utilize special software to design and simulate circuits before building them. This method increases both time and cost efficiency since it does not require the engineer to build every circuit prototype in order to test it. The development of technologies such as VHDL has also eased the burden from engineers by simulating and automatically generating circuit designs.
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.
- Kirchhoff's voltage law: the directed sum of the electrical potential differences around a circuit must be zero.
- Ohm's law: the voltage across a resistor is the product of its resistance and the current flowing through it.
- the Y-delta transform
- Norton's theorem: any two-terminal collection of voltage sources and resistors is electrically equivalent to an ideal current source in parallel with a single resistor.
- Thevenin's theorem: any two-terminal combination of voltage sources and resistors is electrically equivalent to a single voltage source in series with a single resistor.
- Millman's method: the voltage on the ends of branches in parallel is equal to the sum of the currents flowing in every branch divided by the total equivalent conductance.
- See also Analysis of resistive circuits.
Network simulation software
In more complex circuits, engineers need to turn to circuit simulation software. SPICE and EMTP are the most famous of these.Linearization around operating point
When faced with a new circuit, the software first tries to find a steady state solution. This is a solution 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.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 Gauss-Jordan elimination.
Piece-wise linear approximation
This type of simulator uses piece-wise linear approximations of the equations governing the elements of a circuit. This approximation comes down to splitting the circuit into two parts: a completely linear network with a number of terminals that connect to ideal diodes. Every time a diode switches from on to off or vice versa, the linear network is configured differently. Increasing the accuracy of the simulation can be achieved by adding more detail to the approximation of equations, this will increase the running time of the simulation. This flexibility allows an engineer to make a trade-off between simulation time and the precision of the results, something that is not easily done with the previous simulation technique.An example for a software using this technique is the Simulink toolbox PLECS.
See also
- Analysis of resistive circuits
- Alternating current
- Balancing network
- Digital circuit
- Diode bridge
- Direct current
- Quiescent current
- Ground (electricity)
- Impedance
- Load
- Mathematical methods in electronics
- Netlist
- Network analyzer (electrical)
- RC circuit
- LC circuit
- RLC circuit
- Potential divider
- Schematic
- Series and parallel circuits
- SPICE
- Continuity test
- Voltage drop
External links
- Main
- "[All About Electric Circuits]" (2003) : online textbooks covering electricity and electronics.
- [Electronic Circuits Archive] : large collection of circuits
- [Commlinx Circuits] : Database of circuit schematics
- [Discover Circuits] : resource for engineers, hobbyists, inventors & consultants.
- [Electricity and Magnetism]: online textbook
- [Lessons in Electric Circuits]: online textbook
- [Electronic Circuits & Tutorials]: A very helpful Informative collections of Schematics & Tutorials.
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.