r/ECE • u/throwaway8490247 • 3d ago

HOMEWORK (GOOD) Help with Thevenin equivalent circuits

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In advance, I appreciate the help. I know this sub has a "do your own homework" attitude, but I've been staring at this problem for hours and can't figure out how to proceed. I understand TEC circuits pretty well, and had minimal issues with every other problem, but this specific one has stumped me. I've reread my chapter and watched TEC lessons on Youtube, but can't find anything that fits this specific example.

I've got half of this solved. Finding the Thevenin Resistance is simple enough, I shorted the Voltage Sources and opened the Current Source. 1200 +3300 + ((2200*5600)/(2200+5600)) is ~6080 ohms.

Where I'm running into an issue is finding the Thevenin Voltage. If the Load Resistor is opened, then it seems to me that the entire circuit is open. If the circuit is open, then the current source has nowhere to flow, and I can't find the solution. I would convert the current source to a voltage source if I could, but I don't think that can be done, because there is no parallel resistor.

The best solution I've come up with is to find the voltage at the junction between the two voltage sources and their resistors, while treating the current source as non existent because it doesn't have anywhere to flow to. However when testing this result (12.41 V) in a simulator it doesn't seem to work. What am I doing wrong?

Edit: Solved, Thank you everyone for your help. If anyone is having trouble with a problem like this themselves, I worked it out and posted the steps in the comments below.

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u/ee_control_z 3d ago

Just by looking at the figure, I already know its from Sedra.

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u/throwaway8490247 1d ago

It's actually Boylestad. I've never used Sedra, but I really don't like this book. It's so hard to follow, and the example problems usually only get you halfway to the solution on the homework. I typically just read over the chapter to get the idea, then watch youtube lessons until the concept sticks.

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u/ee_control_z 20h ago

Oh, ok. They must use the same circuit editor then because the circuit design art follows what is found in Sedra. ;)