Postby TGTS0907129» Kirchhoff rules of analyzing circuit

Describe the Kirchhoff rules of analyzing circuit


The two principles stated below are so simple as to seem obvious; yet they provide a method for analyzing any circuit carrying either transient or steady-state currents, including alternating currents. The first rule is based on the principal of conservation of charge, namely, that charge is neither created, nor destroyed but only moved from place to place. The second rule is based on the principal of conservation of energy: energy is neither created nor destroyed but only transformed one form to another.

Kirchhoff’s first rule states that at any point in a circuit, the sum of the currents directed toward the point mints the sum of the currents directed away from the point is equal to zero.

Kirchhoff’s second rule states that around any closed path, the algebraic sum of all the changes of potential is zero.

The determination of unknown quantities for a complex circuit calls for the writing of as many independent equations are there are unknowns in the currents, resistance, or other circuit quantities which will be discussed later. Any relationships which provide independent equations are useful. One equation of a set is independent of the others if it is not algebraically equivalent to any of the others or to any combination of other equations; but for always easy to tell whiter an equation is equivalent to a combination of other equations; but for reasonably simple circuits certain rules may be followed, to avoid difficulty.

Consider the circuits in which the emfs and the current values, nor their directions, are known. The first step in the application of Kirchhoff’s rules to this circuit is to identify with letters the five unknown currents I1 through I5. Arbitrary current directions are assigned and indicated by arrows on the diagram. They need not agree with the actual current directions, for if a current is opposite to the assumed direction, its value will be found to be negative. Since the current in a resistor is form the end at higher potential to that at lover, it is help to label with a plus sign the end of each restore at which the current is assumed to enter and label with a minus sign the end  at which the current leaves.

By TGTT06081269 on 9/24/2015 9:43:43 PM
TGTS0907129 on 9/23/2015 11:06:42 PM

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