# Converting to a circuit's Thevenin equivalent?

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1. Feb 5, 2017

### Jayalk97

1. The problem statement, all variables and given/known data

2. Relevant equations
Finding the Thevenin equivalent?

3. The attempt at a solution
I found the thevenin resistance to be 185/47 ohms, which came out to be correct.

I've been struggling with this question all day. I ended up attempting to find the norton equivalent and then converting it, since the question asks for both anyways. I started with a source conversion on the 3A and 5ohm current source and resistor, turning it into a 15V voltage source and a 5 ohm resistor in series (going into the b terminal). I shorted the a-b terminal and used KVL to find the current going through as 3A, typed that into my webwork page and it said I was wrong. Is there anything I'm missing here?

2. Feb 5, 2017

### Staff: Mentor

Are you given values for $I$ and $R$ ?

3. Feb 5, 2017

### Jayalk97

Oh yeah sorry, I = 2.5A and R = 4.5ohms

4. Feb 5, 2017

### Jayalk97

On that note actually, these problems look fairly straightforward and I'm afraid that I misunderstand something fundamental about circuits...

5. Feb 5, 2017

### Staff: Mentor

Okay.

Hint: Work from left to right towards the output, converting and combining sources and resistances as you go.

6. Feb 5, 2017

### Jayalk97

If I have a voltage source>resistor>voltage source>resistor in series could I just rearrange and combine them? If so I converted the leftmost current source and resistor to a voltage source in series with it, combined the 2 resistors and voltage sources to get 25.25V and 18.5 ohms. I converted those to a current source in parallel with a resistor to get 101/74A and 18.5ohms. Adding those to the current source in parallel with the resistor on the right I get 121/74A (pointing down) with 185/47ohms, giving me a voltage difference of 605/94 but the program says that is incorrect...

7. Feb 5, 2017

### Jayalk97

Oh my god it explicitly wanted the voltage from a to b, and that is -605/94. I've been trying to figure this out for four hours... Thank you for the help haha.

8. Feb 5, 2017