1002. dc circuits analysis 1

8/13/2019 1002. Dc Circuits Analysis 1

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DC CIRCUITS ANALYSISDEFINITION OF TERMS

ELECTRIC CIRCUIT: A closed Path consisting of active andpassive elements interconnected and current flow isconfined to the closed path.

Active Elements supply energy(e.g. battery) Passive Element consumes the energy(e.g. resistor)

Movement Of Electrons: Electrons have certain potentialenergy They move from one energy level(a point of high energy) toanther energy level(a point of low energy level) Point of high energy level(high potential) is designated by a

positive sign (+)


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DC CIRCUITS ANALYSISPoint of Low energy(low potential) is designated bynegative sign (-)CURRENT: The rate of flow of electric chargeConditions for the flow of current

There must be a: Complete closed circuit Driving force(an influence i.e. emf)

ELECTROMOTIVE FORCE(EMF): That which tends toproduce an electric current in a circuit (Its unit is volt)ELECTRIC POTENTIAL: The amount of work done per unitcharge between two points(Capacity of a charge to dowork)


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DC CIRCUITS ANALYSISPOTENTIAL DIFFERENCE(pd):

Difference in the potential of two bodies or

The energy transferred due to the passage of a unitcharge between two points in an electric circuit

RESISTANCE: Opposition to the flow of currentResistance of a conductor mainly depends uponLength

AreaNature of the materialR l/ A R = l/ A


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DC CIRCUITS ANALYSISOHMS LAW: The p.d across the ends of a conductor is

proportional to the current flowing through it providedthe physical conditions(temperature, pressure etc)remain constant

V I V = IR


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SERIES AND PARALLEL CIRCUITS

Resistors in SeriesResistors in ParallelSeries parallel Circuits


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RESISTORS IN SERIES

When resistors are connected in series,different P.ds develop across them

the same current flows through them


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RESISTORS IN PARALLEL

When resistors are connected in parallel,different current flows through them

the same p.d develops across them


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SERIES PARALLEL CIRCUITS


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VOLTAGE AND CURRENT DIVISION PRINCIPLE


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VOLTAGE DIVISION PRINCIPLE


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CURRENT DIVISION PRINCIPLE


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KIRCHOFFS LAWS

1. KIRCHOFFS CURRENT LAW 2. KIRCHOFFS VOLTAGE LAW


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KIRCHOFFS CURRENT LAW

States that at any instant the algebraic sum ofcurrent at a junction in network is zero

OR The sum of all currents entering a node equals the

sum of currents leaving the node at any instant oftime.


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KIRCHOFFS VOLTAGE LAW

States that at any instant the algebraic sum ofemfs and the pds in a closed network is zeroOR

The sum of the emfs in any closed loop is equal tothe sum of the potential drops in that loop


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APPLICATION OF KIRCHOFFS LAWS Mesh(Loop) Analysis Nodal Analysis

We shall consider only the loop analysis. Examples.


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THANKS

1002. dc circuits analysis 1

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