1. EGR 101 Introduction to Engineering I1 Resistors in Parallel Resistors connected at a single node pair Voltage across each resistor is the same

2. EGR 101 Introduction to Engineering I2 Caution on Parallel Connection Here, R 1 and R 3 are not in parallel Resistor R 1 is in parallel with the series combination of R 2 and R 3

3. EGR 101 Introduction to Engineering I3 Apply KCL and Ohm’s Law i 1 i 2 i 3 i 4

4. EGR 101 Introduction to Engineering I4 Solving for each current

5. EGR 101 Introduction to Engineering I5 Substitute back

6. EGR 101 Introduction to Engineering I6 Equivalent Circuit

7. EGR 101 Introduction to Engineering I7 Special case for only 2 resistors Product Sum

8. EGR 101 Introduction to Engineering I8 Summary Resistors in parallel have the same voltage The resistors can be replaced by an “equivalent” resistance whose conductance is the sum of the individual conductances The “equivalent” resistor is smaller than the smallest of the individual resistors

9. Classroom Problem #2 EGR 101 Introduction to Engineering I9 Determine the equivalent resistance seen by the current source.