Solving for Vo in terms of Vs/Vx

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In summary, the conversation discusses finding Vx and Vo in a circuit with resistors using voltage division and Ohm's law. The correct expressions for Vx and Vo are (2/5)Vs and (5/6)(0.3Vx), respectively. The units for the combined resistors are in kiloohms, with a combined resistance of 5/6 kΩ or 833Ω. The final expression for Vo is 250Ω*Vx, with no need for a value of Vs.
  • #1
eatsleep
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http://imgur.com/xe52P30
2. Vx= Vs(R1/R1+R2), V=IR
3. I combined the 1k Ω and 5k Ω resistors then used voltage division to find Vx. I used Vx to find Vo which I found to be (5/18)Vx. I don't know where I can do KCL or KVL to solve for Vx.
 
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  • #2
eatsleep said:
attachment.php?attachmentid=58937&stc=1&d=1369225726.gif



2. Vx= Vs(R1/R1+R2), V=IR



3. I combined the 1k Ω and 5k Ω resistors then used voltage division to find Vx. I used Vx to find Vo which I found to be (5/18)Vx. I don't know where I can do KCL or KVL to solve for Vx.

You used voltage division to find Vx. What did you get?

Can you show your work for finding Vo in terms of Vx? The expression you gave doesn't look right to me.
 

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  • #3
Doing voltage division I found Vx = (2/5)Vs. After combining the two resistors on the right side and doing ohm's law I found that Vo = (5/6)(1/.3)Vx = (mistake) is 5/1.8=2.8Vx.
 
  • #4
Check your value for the combined resistors. Pay attention to the units used. Also take a look at your current expression; why do you divide by 0.3S? The current is specified to be 0.3S*Vx.
 
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  • #5
gneill said:
Check your value for the combined resistors. Pay attention to the units used. Also take a look at your current expression; why do you divide by 0.3S? The current is specified to be 0.3S*Vx.

Does .3S not mean .3 Siemens = 1/Resistance ?
 
  • #6
eatsleep said:
Does .3S not mean .3 Siemens = 1/Resistance ?

Yes. And Volts x Siemens = Current. That's a controlled current source.
 
  • #7
gneill said:
Yes. And Volts x Siemens = Current. That's a controlled current source.

Ok, so then Vo=.25Vx?, I also have Vx=.4Vs
 
  • #8
eatsleep said:
Ok, so then Vo=.25Vx?, I also have Vx=.4Vs

Again, what are the units for the two resistors in parallel? How many ohms does their parallel combination make? Your expression for Vx looks okay.
 
  • #9
gneill said:
Again, what are the units for the two resistors in parallel? How many ohms does their parallel combination make? Your expression for Vx looks okay.

They are in kiloohms, their parallel combination makes (5*1)/(5+1) = 5/6 kΩ, 833Ω
 
  • #10
eatsleep said:
They are in kiloohms, their parallel combination makes (5*1)/(5+1) = 5/6 kΩ, 833Ω

Right. Or, if you want to retain accuracy, call it 5000/6 = 2500/3 Ohms. So multiplying your 0.3Vx by 2500/3 gives...
 
  • #11
Vo=250Ω*Vx, so now I have Vx = .4Vs and Vo = 250Vx. I could substituite Vx into Vo, but I do not have a value for Vs.
 
  • #12
eatsleep said:
Vo=250Ω*Vx, so now I have Vx = .4Vs and Vo = 250Vx. I could substituite Vx into Vo, but I do not have a value for Vs.

Nor do you need one... you are looking for Vo in terms of Vs, so a symbolic solution is fine.
 
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  • #13
gneill said:
Nor do you need one... you are looking for Vo in terms of Vs, so a symbolic solution is fine.

Oh well then, thanks for the help.
 

Related to Solving for Vo in terms of Vs/Vx

1. How do you solve for Vo in terms of Vs/Vx?

To solve for Vo in terms of Vs/Vx, you need to use the formula Vo = (Vs/Vx) * Vx. This means that you multiply the value of Vs/Vx by the value of Vx to get the value of Vo.

2. What is the significance of solving for Vo in terms of Vs/Vx?

Solving for Vo in terms of Vs/Vx allows you to express the output voltage (Vo) in relation to the input voltages (Vs and Vx). This can help in understanding the relationship between the input and output in a circuit or system.

3. Can you solve for Vo if you only know the values of Vs and Vx?

Yes, you can solve for Vo if you know the values of Vs and Vx. You can use the formula Vo = (Vs/Vx) * Vx, where Vs and Vx are the input voltages and Vo is the output voltage.

4. How does changing the values of Vs and Vx affect the value of Vo?

Changing the values of Vs and Vx will directly affect the value of Vo. As Vs and Vx increase or decrease, the value of Vo will also increase or decrease proportionally. This relationship is described by the formula Vo = (Vs/Vx) * Vx.

5. What are the units for Vo when solving for it in terms of Vs/Vx?

The units for Vo when solving for it in terms of Vs/Vx will depend on the units of Vs and Vx. For example, if Vs and Vx are in volts, then the unit for Vo will also be in volts.

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