The steps I have done so far are:

1. Found Vx by ignoring the 4 Vx and doing a mesh on the loop which gives me 0.5 for Vx

2. Short circuit Voc

after this i'm stuck. Can someone solve this. My friend got -15v but i'm not sure if he's right. Either way i have to submit this quiz today so if -15v is wrong then i'm getting this question wrong. It would be helpful if someone walked me through the solution though. Thanks.

 

You can also solve it by realizing no current flows through the dependent source, so Vx is a voltage divider output. Then the dependent source makes its negative side 4*Vx lower than the voltage at Vx.

 

You can also solve it by realizing no current flows through the dependent source, so Vx is a voltage divider output. Then the dependent source makes its negative side 4*Vx lower than the voltage at Vx.

Do you mean: Vx=4Vx+Voc
So Voc=Vx-4Vx
Is that what you mean?

 

The steps I have done so far are:

1. Found Vx by ignoring the 4 Vx and doing a mesh on the loop which gives me 0.5 for Vx

According to my math skills your Vx is wrong.

 

Do you mean: Vx=4Vx+Voc
So Voc=Vx-4Vx
Is that what you mean?

I am applying the definition of a voltage source: its positive side is X volts above its negative side, regardless of whether X is a constant or a function.

Since this doesn't load Vx (as there is no current through the dependent source), you can conclude that Voc = Vx - 4Vx because the voltage at the dependent source's positive side is the dependent variable. Since the dependent voltage source is 4Vx volts, its lower side will be 4Vx volts lower than the positive side. Same answer, but different approach.

 

5 volts. simple voltage devider. didnt even need a calulator.

 

5 volts. simple voltage devider. didnt even need a calulator.

Is that your answer to Voc or Vx?

 

voc. this durn thing wants a longer response.

 

voc. this durn thing wants a longer response.

I got -15 V for Voc.

 

The dependent voltage source is open circuit therefore passes no current in this circuit, as tshuck says.

So the 20k and 50k resistors form a simple potential divider, which gives Vx.

The voltage of the dependent source is stated to be 4Vx so its negative end is 20 volts below the node (+5) to which it is coupled.

I make Vx = +5 volts and Voc = -15 volts.

So now you have tshuck's mathematical method and a physical circuit explanation to compare.

 

The steps I have done so far are:

1. Found Vx by ignoring the 4 Vx and doing a mesh on the loop which gives me 0.5 for Vx

2. Short circuit Voc

after this i'm stuck. Can someone solve this. My friend got -15v but i'm not sure if he's right. Either way i have to submit this quiz today so if -15v is wrong then i'm getting this question wrong. It would be helpful if someone walked me through the solution though. Thanks.

In other words, you couldn't solve it and so you just copied your friend's answer and submitted it as your own.

What's your school's policy on academic integrity?

 

Thank you everyone. I made a stupid math error. Appreciate your help