1. Chapter 4-7 Thevenin and Norton Equivalents

2. Thevenin and Norton Equivalents:: Useful when interested at what is taking place at a specific pair of terminals

3. Thevenin equivalent circuit : is a voltage source V Th in series with a resistance R Th. The combination is equivalent to the original circuit at the terminals of interest To find the Thevenin voltage compute the open circuit voltage of the original circuit at the terminals of interest.

4. Example V Th

5. Example R Th

6. The Value? if apply a load across a and b, the voltage across the load, and current will be the same as in the original circuit.

7. You Do

9. Alternative method for finding the Thevenin resistance for a network that contains only independent sources: 1.Deactivate all independent sources A.Short circuit Voltage sources B.Open circuit Current sources 2. Find the equivalent resistance looking into the terminals of interest

11. You Do

12. Alternative method for finding the Thevenin resistance for a network that contains dependent sources: 1.Deactivate all independent sources A.Short circuit Voltage sources B.Open circuit Current sources 2.Leave dependent sources in circuit 3. Apply a small test voltage (v T ), or small test current (i T ), at the terminals of interest 4. Then the Thevenin resistance is the ration of the voltage across the test source to the current delivered by the test source

13. Why did I choose v T ?

15. What is the Thevenin voltage?

16. What you should know 1.Know how to find simple Thevenin and Norton equivalents.