Calculate Vth

• Engineering

current

Relevant Equations:

ohm law
Find the current through the 40ohms resistor using the Thevenin?
I have calculated the Zth = 10 ohms. And I couldn't find the Vth.

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gneill
Mentor
So what have you tried?

So what have you tried?
Nodal method

gneill
Mentor
Nodal method
Okay, possibly not the simplest way forward but let's see your attempt. Where did you get hung up?

Okay, possibly not the simplest way forward but let's see your attempt. Where did you get hung up?
I would prefer not to share it here because the correct answer doesn't match with my solution. Let's say you solving the problem, Can you tell what you're gonna do to solve for Vth?

gneill
Mentor
I would prefer not to share it here because the correct answer doesn't match with my solution. Let's say you solving the problem, Can you tell what you're gonna do to solve for Vth?
Sorry, that's not the way it works here at PF. You need to show your own efforts before we can offer guidance, which includes pointing out missteps in your attempt. No one here will do your homework for you.

If you show your attempted solution then we can spot where it might have gone wrong.

scottdave
Homework Helper
So @Special One if you take the Thevenin Equivalent as across the 40Ω resistor, you would remove that from the circuit, then figure the voltage between those 2 nodes. That is the Thevenin Voltage. Once you have that, then you draw a short circuit between the nodes, and calculate the current through that short.

To find the Thevenin equivalent resistance, just divide: (Thevenin Voltage) ÷ (short circuit current).

As others have said, the way PhysicsForums works, you put what you have attempted, and the other contributors will look and point out where you may have mistakes. That way, you can learn from your mistakes.

https://practicalee.com/thevenin-equivalent/#:~:text=Steps to Find the Thevenin and Norton Equivalent,and series reduction combinations. ... More items...

gneill
Mentor
What next? How can I find Vth?
Above you mentioned attempting nodal analysis. You could show us that attempt, or consider another approach. Here's a thought that might get you thinking along other lines:

Looking at the circuit with the load removed you can pick out three essential nodes. That implies three equations in three unknowns for a nodal analysis approach. However, with the load resistor removed there are only two loops, so you're down to two equations and two unknows.

But it gets better! For a mesh analysis one of the loops has its mesh current fixed by the 10 A current source, so that loop is already solved and you're down to a single equation with one unknown. Find that current then do a little "KVL walk" between the output leads and you're done.

Special One and scottdave