107_07 - 1 Electrical Engineering Technology EET 107...

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Unformatted text preview: 1 Electrical Engineering Technology EET 107 Introduction to Circuit Analysis Lecture # 7 Professor Robert Herrick Purdue University © EET 107 - 7 Introduction to Circuit Analysis 2 Summary KCL – Kirchhoff’s Current Law KCL Simple Node Simple Voltage Node Voltage Super Node Super Purdue University © EET 107 - 7 Introduction to Circuit Analysis 3 KCL Kirchhoff’s Kirchhoff’s Current Current Law Law Purdue University © EET 107 - 7 Introduction to Circuit Analysis 4 KCL – Kirchhoff’s Current Law What flows in must flow out. pipe water out water in node Iin Purdue University © Iout EET 107 - 7 Introduction to Circuit Analysis 5 KCL – Kirchhoff’s Current Law What flows in must flow out. node Iin Iout I in = I out Purdue University © EET 107 - 7 Introduction to Circuit Analysis 6 KCL – Kirchhoff’s Current Law What flows in must flow out. node 2 gal/s 2A pipe 2 gal/s 2A Analogy 2 A = 2A Purdue University © EET 107 - 7 Introduction to Circuit Analysis 7 KCL – Kirchhoff’s Current Law I1 + I 2 = I 3 + I 4 I2 = 7 A I1 = 3 A I4 = 5 A 3A + 7 A = 5 A + 5 A 10 A =10 A I3 = 5 A ∑ I into node = ∑ I out of node Purdue University © EET 107 - 7 Introduction to Circuit Analysis 8 KCL – Two Terminal Devices I into R Iout of supply E Isupply E R R I out of R Iinto supply simplified view com voltage reference Isupply IR IR represents current into and out of the supply. represents current into and out of the resistor. Purdue University © EET 107 - 7 Introduction to Circuit Analysis 9 KCL KCL & The SIMPLE Node The SIMPLE Purdue University © EET 107 - 7 Introduction to Circuit Analysis 10 KCL & The SIMPLE Node What flows in must flow out. I1 = 3 A I2 I1 = 3 A a THINK R E current flowing b I4 I3 I1 = I2 = I3 = I4 Purdue University © EET 107 - 7 Introduction to Circuit Analysis 11 KCL & The SIMPLE Node IR R Isupply E ID D Ι=0 Iwire I supply = I R = I D = I wire Purdue University © EET 107 - 7 Introduction to Circuit Analysis 12 KCL & The SIMPLE Node +E Isupply = 20 mA IR R ID D I 20 mA returns through supply Iwire Current Diagram Bubble Notation Purdue University © EET 107 - 7 Introduction to Circuit Analysis 13 KCL & The SIMPLE Node Isupply a IR2 IR1 E R1 R2 Isupply b IR2 branch currents IR1 THINK current flowing Purdue University © EET 107 - 7 Introduction to Circuit Analysis 14 KCL & The SIMPLE Node 7A 2A a IR1 E R1 5A R2 Node a or b 7A = IR1 + 2A IR1 = 5A b Purdue University © EET 107 - 7 Introduction to Circuit Analysis 15 KCL KCL & The VOLTAGE Node The VOLTAGE Node Purdue University © EET 107 - 7 Introduction to Circuit Analysis 16 KCL & The VOLTAGE Node simple node E Purdue University © R1 EET 107 - 7 R2 R3 Introduction to Circuit Analysis 17 KCL & The VOLTAGE Node top voltage node (bold line) +E E R1 0V Purdue University © R2 R3 bottom voltage node EET 107 - 7 Introduction to Circuit Analysis 18 KCL & The VOLTAGE Node Isupply What flows in top voltage node IR1 IR2 E R1 R2 IR3 must flow out. R3 bottom voltage node Isupply Top or bottom voltage node bottom Isupply = IR1 + IR2 + IR3 Purdue University © EET 107 - 7 Introduction to Circuit Analysis 19 KCL & The VOLTAGE Node Isupply top voltage node THINK IR1 IR2 IR3 current flowing bottom voltage node Purdue University © EET 107 - 7 Introduction to Circuit Analysis 20 KCL & The VOLTAGE Node 9A a 4A IX 5A E R1 3A R2 c IZ 1A b R3 d 1A IZ ? Purdue University © EET 107 - 7 IY Node a 9A = 5A + IX IX = 4A Node b 4A = 3A + IY IY = 1A Introduction to Circuit Analysis 21 Bridge Circuit a R1 E Rload b R2 R3 c R4 d Purdue University © EET 107 - 7 Bridge R1 R2 R3 R4 Introduction to Circuit Analysis 22 KCL & the Bridge Circuit a Isupply IR1 R1 b E Isupply IR2 R2 Rload Iload IR3 Iload Possibilities R3 c IR4 R4 • flow right • flow left d • 0A (no current) Purdue University © EET 107 - 7 Introduction to Circuit Analysis 23 KCL & the Bridge Circuit Node a a Isupply IR1 R1 b E Isupply IR2 R2 Rload Iload IR3 R3 c IR4 Isupply = IR1 + IR3 R4 Node b d IR1 = IR2 + Iload Purdue University © EET 107 - 7 Introduction to Circuit Analysis 24 KCL & the Bridge Circuit 6A a 9A R1 E 3A b R2 5A IR3 Rload -2A Iload IR4 R3 c R4 d 2A flows other direction ! Purdue University © EET 107 - 7 Node a 9A = 3A + IR3 IR3 = 6A Node b 3A = 5A + Iload Iload = −2A Introduction to Circuit Analysis 25 KCL & the Bridge Circuit a 9A R1 3A b E R2 5A Rload 2A 6A R3 c 4A R4 d Total solution of currents! Purdue University © EET 107 - 7 Introduction to Circuit Analysis 26 KCL KCL & The SUPER Node The SUPER Purdue University © EET 107 - 7 Introduction to Circuit Analysis 27 KCL & the SUPER NODE super node 9A R1 E 9A R2 6A Rload 2A R3 R4 4A Super node includes components/circuits. Purdue University © EET 107 - 7 Introduction to Circuit Analysis 28 KCL & the SUPER NODE super node 9A R1 E 9A R2 6A Rload 2A R3 R4 4A What flows in must flow out. ∑ I into node = ∑ I out of node 9A + 2A + 4A = 9A + 6A 15A = 15A Purdue University © EET 107 - 7 Introduction to Circuit Analysis 29 KCL & the SUPER NODE Isupply R1 3A 5A E R2 R3 IR4 R4 Rload Iload 1A 7A Isupply = ? 8A Purdue University © ∑ I into node = ∑ I out of node 3A + 5A = 1A + IR4 IR4 = 7A Iload = ? 2A EET 107 - 7 Introduction to Circuit Analysis 30 Team Activity Know Know Your Your KCL ! KCL Purdue University © EET 107 - 7 Introduction to Circuit Analysis 31 Summary KCL – Kirchhoff’s Current Law KCL Simple Node Simple Voltage Node Voltage Super Node Super Purdue University © EET 107 - 7 Introduction to Circuit Analysis ...
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