r1 r2 r3 r3 v i1234 r1234 r4

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: drop across is IRi Reffective = R1 + R2 + R3 + ... Resistors in parallel: 1 Voltage drop across is same. Reffective Current through is V/Ri Solved Circuits R2 R1 V 11 1 = + + + ... R1 R2 R3 = R3 V I1234 R1234 R4 Physics 212 Lecture 10, Slide 5 Physics 212 Lecture 10, Slide 5 Last Time Physics 212 Lecture 10, Slide 6 Physics 212 Lecture 10, Slide 5 New Circuit R1 R3 V1 V2 R2 How Can We Solve This One? R1 V1 V2 R3 R2 = V I1234 R12 THE ANSWER: Kirchhoff’s Rules Physics 212 Lecture 10, Slide 7 Physics 212 Lecture 10, Slide 5 Kirchoff’s Voltage Rule ∑ ∆V i =0 Kirchoff's Voltage Rule states that the sum of the voltage changes caused by any elements (like wires, batteries, and resistors) around a circuit must be zero. WHY? The potential difference between a point and itself is zero ! Physics 212 Lecture 10, Slide 8 Physics 212 Lecture 10, Slide Kirchoff’s Current Rule ∑I in = ∑ I out Kirchoff's Current Rule states that the sum of all currents Kirchoff's entering any given point in a circuit must equal the sum of all currents leaving the same point. WHY? Electric Charge is Conserved Physics 212 Lecture 10, Slide 9 Physics 212 Lecture 10, Slide Checkpoint 1 How many potentially different currents are there in the circuit shown? A. 3 B. 4 C. 5 D. 6 E. 7 “two for the parallel branch and then one for the first two and last resistors .” and A “There are four different series connections” B C “there is D there potentially one between every pair of resistors.” resistors.” Physics 212 Lecture 10, Slide 10 Physics 212 Lecture 10, Slide Checkpoint 1 How many potentially different currents are there in the circuit shown? I1 I3 I2 I1 A. 3 B. 4 C. 5 I3 D. 6 E. 7 Look at the nodes! Top node: A B Bottom node: C D I1 flows in, I2 and I3 flow out I2 and I3 flow in, I1 flows out That’s all of them! Physics 212 Lecture 10, Slide 11 Checkpoint 2 In the following circuit, consider the loop abc. The direction of the cu...
View Full Document

Ask a homework question - tutors are online