PHY 114 Lecture 8: Lecture 8
Document Summary
Assign currents to each branch of the circuit. Find the unknown currents (current in each resistor) in the diagram below: *red markings were initially not there and were filled in* *he guessed wrong in this diagram because the current for i2 should be moving right, not left* Loop edcfe: 1 - i1r1 - i2r2 = 0. Loop afcba: 2 + i2r2 - i3r3 = 0. Could also use junction f for the above equation. Just the idea that current going in = current going out. The main point is to write down three equations for the three unknown currents: (1) i1r1 + i2r2 = e1 (2) i3r3 - i2r2 = e2 (3) i1 = i2 + i3. This can be equation (4) ((r1 + r2)i2) + (r1 * i3) = e1. Multiply the top equation by -r3 and the bottom equation by. Then solve for i2 (-r3(r1 + r2)i2) - (r1r3i3) + (r1r3i3) - (r1r2i2) = (r1e2) - (r3e1)
