Circuit Analysis

Superposition

1. Identify all power sources

2. Consider all the effects of each one and deactivate the others

3. For the selected source, find the unknown voltage/current

4. Repeat steps 2 and 3 for all sources

5. Find the algebraic sum of the results I = I(a) + I(b)

Thevenin’s Equivalent Circuit ( Thereom)

Any collection of power sources and resistances connected between two terminals = voltage source and a single resistance connected in series between the same two terminals

Thevenin’s Equivalent Voltage (VTH)

The open circuit voltage between two terminals

Thevenin’s Equivalent Resistance (RTH)

Total circuit resistance with all power sources off

Thevenin’s Equivalent Circuit ( process)

1. Create an open circuit

2. Calculate the open circuit voltage between terminals = VTH

3. Calculate the equivalent resistance between terminals while all power sources deactivated = RTH

4. Draw Thevenin’s Equivalent Circuit

Nodal Analysis

1. Identify all nodes

2. Select one node as the reference node to have 0V

3. Apply KCL to each of the non-reference nodes, using Ohm’s Law to express the current in terms of NODE voltages

4. Solve the simultaneous equations

5. Use the derived values of the node voltages to determine the current in each branch of the circuit

What does Thevenin’s Equivalent Circuit look like?