1. ECE 1270: Introduction to Electric Circuits
Lecture 10:
Thevenin Equivalent Sources
Chapter 4
Techniques of Circuit Analysis: Sections 4.11

2. Technique#1 to find RTH
If the circuit contains independent sources....
1) First find VTH
2) To find RTH:
Replace voltage source with a short
Replace current source with an open

3. p4.78b: Find RTH and VTH
GND

4. Another Example: Sadiku (4th ed) p4.39
Students work on this problem

5. Technique#2 to find RTH If the circuit contains dependent sources....
1) Deactivate independent sources (voltage->short, current->open)
2) Apply test voltage source VT and find IT
To find RTH:
RTH=VT/IT
Example 4.9 (Sadiku 4th edition)
Lengthy Problem. Go slow. Students must understand all the steps clearly.

6. p4.79 (mistake in solution manual: direction of i∆?)

7. AP 4.20 Students work on this example Vth:
First do source transformation on the 4A 60 ohm on the left. Combine 60+20=80 with a voltage source =240 V.
Then supernode for eq.1, write eq. for dependent source for eq.2
Rth:
Short the 240 V source.
Write supernode eq., sub for idelta and solve for VT/IT=RTH