I am not supposed to change the components in the box here. So, to find Thevenin resistance, I added in a 1A current source and figured Voc would be equal to Rt. But Voc keeps coming up as 15, and I checked that no other hidden impedances exist, so why is it coming up like this?

 

Because the voltage that the current source has to produce in order to push 1 A through that circuit is 15 V.

Do the analysis by hand, it's trivially easy. If you replace the voltage-controlled switch with it's 1 Ω 'on' resistance, what is Vout going to be if there is 1 A flowing through the circuit? You should be able to do it in your head.

 

Because the voltage that the current source has to produce in order to push 1 A through that circuit is 15 V.

Do the analysis by hand, it's trivially easy. If you replace the voltage-controlled switch with it's 1 Ω 'on' resistance, what is Vout going to be if there is 1 A flowing through the circuit? You should be able to do it in your head.

I have to use LTSpice as per instructions but when I do it in my head I still find that Vout is supposed to be 15 V. But isn't Rt supposed to be 10 ohms since that would be the Req of this circuit?

 

I have to use LTSpice as per instructions but when I do it in my head I still find that Vout is supposed to be 15 V. But isn't Rt supposed to be 10 ohms since that would be the Req of this circuit?

Was I supposed to substract 5V from it because the current source is creating current opposite the direction of the one created by the voltage source?

 

I have to use LTSpice as per instructions but when I do it in my head I still find that Vout is supposed to be 15 V. But isn't Rt supposed to be 10 ohms since that would be the Req of this circuit?

So if you agree that Vout is going to be 15 V, but that the equivalent resistance is 10 Ω, then perhaps it's time to take a step back and reevaluate how you are trying to determine Rt. Consider what you have been taught about what the equivalent resistance is and how to determine it. You are overlooking something pretty fundamental.

 

Was I supposed to substract 5V from it because the current source is creating current opposite the direction of the one created by the voltage source?

Presumably you are supposed to be treating the circuit as a black box, meaning that you don't know that there is a 5 V source inside of it. If that's not the case, then the exercise is pretty pointless because you can simply determine Rt by inspection, as you've already done.

 

Presumably you are supposed to be treating the circuit as a black box, meaning that you don't know that there is a 5 V source inside of it. If that's not the case, then the exercise is pretty pointless because you can simply determine Rt by inspection, as you've already done.

I will think more about it
Thank you for your help