In this presentation a two-loop circuit is analyzed: animation is used to demonstrate choosing current direction and generating resistor polarities Creating a junction point equation the idea of generating loop equations by “walking the loop” is demonstrated via an animated “robot cockroach voltmeter.” Simply click through the slides and provide your own narration

Kirchhoff Junction Points and Loop Walks By Leo Takahashi, The Pennsylvania State University, Beaver Campus

A circuit is constructed with known battery emfs ( દ 1 and દ 2 ) and known resistances (R 1, R 2, and R 3 ); we wish to know the values of the currents.

We will use Kirchhoff’s Rules as follows: At a JUNCTION POINT the currents in must equal the currents out. Around any CLOSED LOOP the sum of the potential differences (voltages) must equal zero.

V દ1દ1 દ2દ2 R1R1 R2R2 R3R3 I1I1 I2I2 I3I3 a b At a: I 1 = I 2 + I 3 V = 0 - I 1 R 1 - I 2 R 2 V + I 2 R 2 - દ 2 - I 3 R 3 = 0 +દ1+દ1 Loop 1 Loop 2

These three equations I 1 = I 2 + I 3 દ 1 – I 1 R 1 – I 2 R 2 = 0 I 2 R 2 – દ 2 – I 3 R 3 = 0 can be solved for the three unknown currents.