[SOLVED] How to calculate Vout?

Discussion in 'Homework Help' started by ItzKitkat, Nov 9, 2014.

  1. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    How to calculate Vout that will be displayed on the multimeter, which has an internal resistance of 70kΩ

    Vin = 17v
    R1 = 30kΩ
    R2 = 5kΩ

    I know the formula to calculate Vout but I have no idea where to put the 70kΩ.
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Draw a schematic.
    That will show how the resistors and meter are connected.

    Bertus
     
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  3. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    Ok, I drew a schematic. I can see that the multimeter is connected in parallel.
     
  4. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Where do you need to "measure" the voltage?
    As you have drawn it now, it is right across the power source.

    Bertus
     
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  5. b1u3sf4n09

    Member

    May 23, 2014
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    Treat your multimeter like a resistor in parallel with your load resistors. This will create 2 resistors in parallel, 30kΩ + 5kΩ = 35kΩ and 70kΩ. Then you can find the current flowing through each leg, and from that obtain the voltage across each.
     
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  6. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    It says we need to calculate Vout voltage that will be displayed on the multimeter.
     
  7. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Where is Vout?
    Is it the voltage across the 5K resistor?

    Bertus
     
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  8. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    I am not sure where is Vout. The question does not provide a schematic.
    No
     
  9. ISB123

    Well-Known Member

    May 21, 2014
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    I'm pretty sure that task asks for Vout on the voltage divider.
     
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  10. b1u3sf4n09

    Member

    May 23, 2014
    115
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    Post the exact question, with the exact provided information. Anything less will just produce guess work.
     
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  11. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    Here is the exact question.

    Calculate the Vout value that will be displayed on a multimeter with an internal resiatance of 70kΩ where:

    Vin = 17v

    R1 = 30kΩ

    R2 = 5kΩ

    Anster to at least 3 decimal places.
     
  12. b1u3sf4n09

    Member

    May 23, 2014
    115
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    Does it make any mention of the configuration R1 and R2 are in? In series or in parallel? How did you generate the schematic you drew?
     
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  13. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    I guessed it :(
     
  14. b1u3sf4n09

    Member

    May 23, 2014
    115
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    Is this from a textbook? Or was this generated by a teacher? If it is the former, could you post a screenshot of the question? If it is the latter, then your teacher will have to provide more information for this to be solvable.
     
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  15. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    It is randomly generated. I guess I have ask the teacher. Thanks for helping
     
  16. ISB123

    Well-Known Member

    May 21, 2014
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    That's really irresponsible of your teacher.
     
  17. WBahn

    Moderator

    Mar 31, 2012
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    If it is randomly generated, then it is almost certainly referring to a diagram that defined the configuration and the variables and the random generation is just coming up with specific values for the problem.
     
  18. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,373
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    Good guess. How will you do the next time? Will you get it correct?
     
  19. ItzKitkat

    Thread Starter Member

    Nov 9, 2014
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    0
    UPDATE: there was a schematic missing. Here is the schematic.

    Vin= 16V
    r1 =15 Kohms
    r2=15 kohms

    edit: is it 8 volts?
     
    Last edited: Nov 16, 2014
  20. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,387
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    It is voltage divider. The formula is simple. Use it.
     
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