Solve Thevenin Problem: Find Rth & Vth for Points A+B

[Sastronaut]

Homework Statement

Use thevenin techniques to find the equivalent circuit (Rth and Vth) to which the points A + B are attached.

Homework Equations

Kirchoffs loop rules
V=IR

The Attempt at a Solution

I have indicated my chosen loops in blue. I am not quit sure at this point how to apply kirchhoffs loop rule to each of the loops so that I can determine Vth. the only loop I felt confident on was number 1 i.e. 1: 5V-40ΩI1+Vth. There so much going on in the circuit that its hard from me to determine which way current is flowing so that I can create a junction rule for the wire between the yellow points. Any help would be greatly appreciated!

 

[phinds]

So why not redraw the circuit so that it looks less confusing?

Also, your loops 1 and 2 are useless since they "loop" around open circuits, which are not really loops at all.

 

[Sastronaut]

how do you purpose I re-draw it

 

[phinds]

It was a suggestion. Don't do it if you don't want.

You have not addressed my comment about your loops 1 and 2

 

[paranormal]

I would approach this problem by first carefully studying the given circuit and identifying the key components and their relationships. This would involve analyzing the circuit using Kirchhoff's laws and Ohm's law to determine the current and voltage at each point. Once I have a clear understanding of the circuit, I would then use Thevenin's theorem to simplify the circuit and determine the equivalent circuit at points A+B.

To find the Thevenin equivalent circuit, I would follow these steps:

1. Identify the load resistor: In this case, the load resistor is the 40Ω resistor between points A and B.

2. Calculate Rth: To find Rth, I would first remove the load resistor and replace it with a short circuit. Then, I would calculate the equivalent resistance of the remaining circuit between points A and B. This would be the Rth for the Thevenin equivalent circuit.

3. Calculate Vth: To find Vth, I would use Kirchhoff's voltage law (KVL) to determine the voltage drop across the removed load resistor. This would be the same as the voltage at points A and B in the original circuit. Therefore, Vth would be equal to the voltage drop across the removed load resistor.

4. Draw the Thevenin equivalent circuit: Once I have calculated Rth and Vth, I would draw the Thevenin equivalent circuit, which would consist of a voltage source with Vth as its voltage and a resistor with Rth as its resistance.

In summary, to solve the Thevenin problem at points A+B, I would use my knowledge of Kirchhoff's laws, Ohm's law, and Thevenin's theorem to simplify the circuit and determine the equivalent circuit at those points. This approach would allow me to accurately determine the values of Rth and Vth.