ECEN 215, Principles of Electrical EngineeringDr. Mina RahimianLecture# 2 Date: 8/28/13Ex. The power associated with element "a" and "b" are given. Find the power of element "c".Five Basic Circuit Elements:- voltage source- current source- resistor- inductor- capacitorIdeal SourcesThere are two types of ideal sources: dependent sources and independent sources.An independent source provides a specified voltage or current independent of the other circuit elements connected to it.independent voltage source: maintains the specified voltage regardless of the current passing through it.independent current source: maintains the specified current regardless of the voltage across it.The relationship between the voltage and current of an independent source is determined by the other elements connected to it.Dependent SourcesThe value of a dependent sourse is controlled by another voltage or current in the circuit.There are 4 types of dependent sources:a) voltge controlled voltage sourceb) current controlled voltage sourcec) voltage controlled current sourced) current controlled current sourceEx. Which interconnection is valid?Ex. Compute the power associated with each element.practice problem:a) What value of "a" is required in order for the interconnection to be valid?b) Find the power associated with the 25v source.ResistorResistance is the capacity of material to resist the flow of electric current. It is denoted by R andmeasured in ohms.Resistor is a circuit element used to model the current resistivity of the resistor.Basic Laws: Ohm's law, Kirchhoff's current law (KCL), Kirchhoff's voltage law (KVL).Ohm's Law: The ratio of voltage to current of a resistor is constant and equals the resistance of the resistor.Conductance is the reciprocal of resistance, denoted by G and measured in Siemens (S).Power for resistorsEx. Calculate the unknown voltage or current and determine the power dissipated in each resistor.Ex. A 47 K-ohm resistor has a power rating of 0.25 W. Determine the maximum current and voltage that can be applied to the resistor.Electric Circuit ModelsThe circuit elements are used to construct the circuit model for practical systems.Example: circuit model of a flashlightExample: Headlight circuit modelAnalogy of fluid flow system to electric circuits:Voltage source ==> pumpConductor ==> pipeCurrent ==> flow rateVoltage ==> pressure differenceSwitch ==> valveresistance ==> constrictionDefinition of some termsNode: The connection point between two or more circuit elements is called a node.Loop: Any closed path in the circuit is called a loop.Series connected elements: When two or more elements are connected sequentially, they have the same current and are said to be in series.Prallel connected elements: When two or more elements are connected between the same node pair, they have the same voltage and are said to be in parallel.Ex. Identify the nodes, series elements and parallel elements.Kirchhoff's Curent Law (KCL) : The algebric sum of all currents entering a node (or a closed boundary) is zero.Kirchhoff's Voltage Law (KVL): The algebric sum of all voltages around any loop in the circuit is