Resistance Ratios Click within the blue frame to access the control panel. Only use the control panel (at the bottom of screen) to review what you have seen. This presentation is partially animated. When using your mouse, make sure you click only when it is within the blue frame that surrounds each slide. A G Inc. “We don’t need no stinking resistance ratios”

Your comfort level with your responses to the following 2 question assessment tool should indicate if the presentation that follows will increase you knowledge base on the topic outlined by the questions in this tool. Pre-presentation Self Assessment Activity

1)Consider any representative series circuit example. Are resistance ratios used to find the voltage drops across each resistor? Are resistance ratios used to find the amount of current flowing through each resistor? (a) (b) V real R 1 V 1 R 2 V 2 I 1 I 2 A circuit is analyzed when you know the amount current flowing through and the voltage drop across each circuit element. Everybody is suppose to remember and know how to use Ohm’s law.

Pre-presentation Self Assessment Activity 2)Consider any representative parallel circuit example. Are resistance ratios used ratios to find the voltage drops across each resistor? Are resistance ratios used to find the amount of current flowing through each resistor? (a) (b) A circuit is analyzed when you know the amount current flowing through and the voltage drop across each circuit element. Everybody is suppose to remember and know how to use Ohm’s law. V real R 1 V 1 R 2 V 2 I 2 I 1

Any example of a real series circuit 2 views of the same world Thevinin’s analysis strategy Voltage values are important, current values are easy to get after that. Use resistance ratio’s to find voltage drop values. V 1 R 1 = R 2 R 1 + V real V 2 R 2 = R 2 R 1 + V Norton’s analysis strategy Current values are important, voltage values are easy to get after that. V real R 1 R 2 V 1 V 2 I 1 I 2 Use Ohm’s law = I i R i V i Note: i can equals 1 or 2.

Any example of a real series circuit 2 views of the same world Thevinin’s analysis strategy Voltage values are important, current values are easy to get after that. Use resistance ratio’s to find voltage drop values. V 1 R 1 = R 2 R 1 + V real V 2 R 2 = R 2 R 1 + V Norton’s analysis strategy Current values are important, voltage values are easy to get after that. Resistance ratio’s- “we don’t need any resistance ratios!” I 1 = I 2 I total = R eq R 2 R 1 += V real R 1 R 2 V 1 V 2 I 1 I 2 Use Ohm’s law Note: i can equals 1 or 2. = I i R i V i = I i R eq V real Note: i can equals 1 or 2. = I i R i V i

2 views of the same world Thevinin’s analysis strategy Voltage values are important, current values are easy to get after that. V 1 = V real V 2 = Norton’s analysis strategy Resistance ratio’s- “we don’t need any resistance ratios!” = V real I total R eq V real R 1 V 1 R 2 V 2 I 2 I 1 Use resistance ratio’s to find current flows in each branch. Any example of a real parallel circuit Current values are important, voltage values are easy to get after that. Use Ohm’s law Note: i can equals 1 or 2. = I i R i V i = I i R i R j R j + I total I 1 + I 2 I = when R 2 R 1 + = R eq 111 i can equals 1 or 2. j can equals 1 or 2. Note: But i can not = j Use Ohm’s law = I i R i V i

2 views of the same world Use Ohms’ Laws to find other parameter. Summary V real R 2 I 2 V 2 R 1 I 1 V 1 Thevinin’s strategy Resistance ratio’s- “we don’t need any resistance ratios!” Use resistance ratio’s to find current flows in each branch. Norton strategy Thevinin’s strategy Resistance ratio’s- “we don’t need any resistance ratios!” Use resistance ratio’s to find voltage drops V real R 1 R 2 V 1 V 2 I 1 I 2 Norton strategy

2 views of the same world In either case, use Ohms’ Laws to find other parameter for each resistor. Three Take home messages In series circuits, resistor ratios give you the voltage drops across resistors. In parallel circuits, resistor ratios give you the current flowing through the resistors.

Post-presentation Self Assessment Activity 1)Consider any representative series circuit example. Are resistance ratios used to find the amount of current flowing through each resistor? (b) Everybody is suppose to remember and know how to use Ohm’s law. V real R 1 R 2 V 1 V 2 I 1 I 2 Are resistance ratios used to find the voltage drops across each resistor? (a) Thevinin’s analysis strategyNorton’s analysis strategy NoYes Thevinin’s analysis strategyNorton’s analysis strategy No

Post-presentation Self Assessment Activity 2)Consider any representative parallel circuit example. Are resistance ratios used to find the amount of current flowing through each resistor? (b) Everybody is suppose to remember and know how to use Ohm’s law. Are resistance ratios used to find the voltage drops across each resistor? (a) Thevinin’s analysis strategyNorton’s analysis strategy No Thevinin’s analysis strategyNorton’s analysis strategy YesNo V real R 2 I 2 V 2 R 1 I 1 V 1

End of Presentation A G Inc.