Find total resistance in a network

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Discussion Overview

The discussion revolves around finding the total resistance in a network and calculating the current ##I_x## using Kirchhoff's Current Law (KCL). The scope includes technical reasoning and problem-solving related to electrical circuits.

Discussion Character

  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant proposes applying KCL to a specific node in the circuit to derive an equation involving the voltage ##V## and current ##I_x##.
  • Another participant points out an error in the initial approach regarding the summation of voltage terms and suggests simplifying the circuit by combining current sources and resistors.
  • A later reply indicates that the participant successfully solved the problem, arriving at a value of ##I_x = - 1.5 mA##, but does not provide details on the method used to reach this conclusion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the initial approach to the problem, as one participant identifies an error in the calculations. However, the final value for ##I_x## is presented without further dispute.

Contextual Notes

The discussion does not clarify the assumptions made regarding the circuit configuration or the specific definitions of terms used, which may affect the interpretation of the results.

STEMucator
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I can't get this last problem in the chapter. I am asked to find ##I_x## in the following network:

Screen Shot 2014-09-20 at 9.32.10 PM.png

My first hunch was to apply KCL to the node above the ##2I_x## source:

##10 + 2I_x - \frac{V}{2} - 3 + I_x + \frac{V}{5} + \frac{V}{10} = 0##

Where I have assumed the voltage ##V## is across all components in parallel. From here I've tried various things, but to no avail.
 
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your v/5 term and your v/10 term add up to be Ix, but you've added them in again anyway. Not good.

can you compress the 10ma and 3ma sources down to one source and reduce all the resistors down to one resistor to get an expression for V that is only in terms of Ix and the total resistance?

That's probably too many hints already. You should be able to take it from there.
 
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phinds said:
your v/5 term and your v/10 term add up to be Ix, but you've added them in again anyway. Not good.

can you compress the 10ma and 3ma sources down to one source and reduce all the resistors down to one resistor to get an expression for V that is only in terms of Ix and the total resistance?

That's probably too many hints already. You should be able to take it from there.

Thank you sir, every problem in chapter 2 is now complete (there was a lot in this chapter, > 100). I obtained ##I_x = - 1.5 mA##.

I can finally take it easy after all that, feels like an abyss in my brain right now. I owe you one.
 
Zondrina said:
Thank you sir, every problem in chapter 2 is now complete (there was a lot in this chapter, > 100). I obtained ##I_x = - 1.5 mA##.

I can finally take it easy after all that, feels like an abyss in my brain right now. I owe you one.

Glad to hear it.
 
Last edited:

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