ECE 201 Section 4 Lecture 11 Prof Peter Bermel February 3 2012 HW 6 7 For HW 6 N 100 81 21 For HW 7 N 96 69 34 2 3 2012 Exam 1 Thursday Feb 9 Review session on Monday Feb 6 at 7 pm LILY 1105 Posted 3 sample exams on Blackboard to help you study Extended TA office hours Thurs until 7 30 pm I ll have office hours 9 30 10 30 am MWF in EE 330 and by appointment 2 3 2012 Source Transformations Combining voltage sources Vb Va Vc Va Vb Vc Combining current sources Ia Ib Ia Ib Ic Ic 2 3 2012 Source Transformation Theorem The following 2 terminal networks are equivalent Voltage source Va in series with resistor R Current source Ib Va R in parallel with resistor R Va R Ib R 2 3 2012 Source Transformation Va R Ib R V If 2 3 2012 Example 1 What current flows through the central 3 resistor 3 12 36 V 2 3 2012 6 30 V 40 40 V 24 48 V Example 1 Solution 3 12 36 V 6 30 V 40 40 V 24 48 V Rewrite each of the resistor voltage source pairs as parallel resistor current source pairs with currents of 36 12 3A 30 6 5A 40 40 1A 48 24 2A 2 3 2012 Example 1 Solution 3 3A 5A 12 6 40 24 1A Combine parallel current sources and resistors IL 3 5 8 A IR 1 2 3 A RL 1 6 1 12 1 4 RR 1 24 1 40 1 15 2 3 2012 2A Example 1 Solution 3 8A 4 15 Transform back into V R pairs VL 32 V VR 45 V 2 3 2012 3A Example 1 Solution 3 4 32 V 15 45 V Combine in series V 13 V R 22 I V R 0 59 A 2 3 2012 Equivalent Networks Equivalent networks distinct 2 terminal circuits which exhibit the same currentvoltage relationship Examples 8V 4 2A 4 V 8 4 2 3 2012 4 2 Equivalent Network Examples 1 5A 0 5A 12 6 12 18 V 4 2 2 3 2012 6 3V 8 4 Car Battery Problem What is the minimum value of Vo required to achieve a 50 A starter voltage 50 A 0 02 12 V 2 3 2012 0 02 Vo 0 2 Car Battery Solution 50 A 0 02 12 V 0 02 Vo 0 2 Source transformation yields I 12 Vo 0 02 Req 0 01 W V 6 0 5Vo I 50 6 0 5Vo 0 21 Vo 9 V 2 3 2012 Homework HW 9 solution posted today HW 10 due today by 4 pm in MSEE 230 note the changed location for today only HW 11 due Monday DeCarlo Lin Chapter 5 Problem 41 Problem 43 2 3 2012 Last Lecture on Exam 1 Monday begins Exam 2 material 2 3 2012
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