Electronic – Trouble finding Thévenin equivalent for this circuit

dcthevenin

I'm having trouble finding the thevenin equivalent for this circuit

circuit diagram

To solve this problem, I changed the voltages from 20V and 5V to 25V and 0V as shown below

other circuit diagram

My resulting output voltage is 10V and the Thévenin resistance is 6K ohms. Now the answers says that the output voltage is 5V and 6K ohms.

Confused, I tried a different method, superposition

superposition

and I still got the same output voltage of 10V!

Have I done my circuit analysis correctly, or am I missing a crucial step???

Best Answer

I changed the voltages from 20V and 5V to 25V and 0V

My resulting output voltage is 10V

Yes it is correct, but with respect to \$-5V\$

You forgot to offset the voltage by \$5V\$.

\$ -5V+5V = 0V\$

\$ 20V+5V = 25V\$

And when calculating the result substract what you added:

\$ 10V-5V = 5V\$ with respect to ground (\$0 V\$).