# [SOLVED] How to calculate Vout?

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

1. ### ItzKitkat Thread Starter Member

Nov 9, 2014
33
0
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
15,648
2,346
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
33
0
Ok, I drew a schematic. I can see that the multimeter is connected in parallel.

File size:
12.3 KB
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4. ### bertus Administrator

Apr 5, 2008
15,648
2,346
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
115
14
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
33
0
It says we need to calculate Vout voltage that will be displayed on the multimeter.

7. ### bertus Administrator

Apr 5, 2008
15,648
2,346
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
33
0
I am not sure where is Vout. The question does not provide a schematic.
No

9. ### ISB123 Well-Known Member

May 21, 2014
1,239
527
I'm pretty sure that task asks for Vout on the voltage divider.

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10. ### b1u3sf4n09 Member

May 23, 2014
115
14
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
33
0
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
14
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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Nov 9, 2014
33
0
I guessed it

14. ### b1u3sf4n09 Member

May 23, 2014
115
14
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
33
0
It is randomly generated. I guess I have ask the teacher. Thanks for helping

16. ### ISB123 Well-Known Member

May 21, 2014
1,239
527
That's really irresponsible of your teacher.

17. ### WBahn Moderator

Mar 31, 2012
17,743
4,795
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
1,159
Good guess. How will you do the next time? Will you get it correct?

19. ### ItzKitkat Thread Starter Member

Nov 9, 2014
33
0
UPDATE: there was a schematic missing. Here is the schematic.

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

edit: is it 8 volts?

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File size:
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Views:
37
Last edited: Nov 16, 2014
20. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,387
497
It is voltage divider. The formula is simple. Use it.