Voltage B to D in a simple Circuit

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Homework Help Overview

The discussion revolves around calculating the voltage between points B and D in a simple circuit, utilizing concepts from circuit analysis such as Kirchhoff's Voltage Law (KVL) and Ohm's Law.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore the relationship between total voltage and resistance in the circuit, with some attempting to calculate current and voltage drops across specific resistors. Questions arise regarding the necessity of finding multiple currents and the clarity of the problem-solving approach.

Discussion Status

The discussion reflects a mix of attempts to calculate current and voltage, with some participants expressing frustration over the process. Guidance has been offered regarding the approach to finding current, but there is no explicit consensus on the next steps or interpretations of the problem.

Contextual Notes

Some participants express confusion and frustration about the problem-solving process, indicating a struggle with the concepts involved. There is a mention of forum rules regarding the level of assistance provided, emphasizing a learning-focused approach.

Justkiller91
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Homework Statement



For the network, calculate the voltage B to D

[IMG=http://img13.imageshack.us/img13/1478/66772606.jpg][/PLAIN]

Homework Equations


KVL, and Ohms law.


The Attempt at a Solution


This is what i have:
45v-25v=Vt=20v

Rt=4k+3K+2K=9k ohms
From here on i am not sure what i am supposed to do.
 
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Well, you have the total voltage around the loop and the total resistance around the loop. Think you could get the current flowing? If you had that, what might you do next?
 
I = V/R It = 20/9k=2.2mA
Now that I have that would i just use current divider formula?:

I= Rt/Rx*It Iab = 9k/2k*2.2mA = 9.9mA? Then would i just continue to find the currents?
 
Justkiller91 said:
... Then would i just continue to find the currents?

Uh ... WHAT currents? You've already found the current. Do you have some reason to think there is more than one?
 
This is frustrating and no help what so ever, obviously i am struggling with the problem and haven't been able to figure out what i need to do. Thanks for your time, I know mine has been wasted.
 
The current in the circuit is (45v - 25v)/(2k+3k+4k) = 2.2mA.

The voltage across r2 is (3k)(2.2mA) = 6.666v, with r2's positive at C.

So voltage across BD is 45v - 6.666v = 38.333v with positive at B.
 
Minki said:
The current in the circuit is (45v - 25v)/(2k+3k+4k) = 2.2mA.

The voltage across r2 is (3k)(2.2mA) = 6.666v, with r2's positive at C.

So voltage across BD is 45v - 6.666v = 38.333v with positive at B.

It's good that you want to be helpful but please re-read the forum rules. It is not the purpose of this forum to spoon-feed answers but rather to help folks learn how to solve problems.

I can see that the OP's frustration might have led you to charitably just give him the answer rather than continue to try to lead him to it, but again ... that's not what we do here.
 
Oh OK, no problem, makes sense; I shall be more Socratic in future :)
 
Thank you very much Minki, this has help a great amount. I now know how to solve this as well as similar problems
 
  • #10
Glad to be of help :)
 

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