Solving Voltage/Current in Resistor Circuits

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Homework Help Overview

The discussion revolves around two problems involving resistor circuits connected to DC voltage sources. The first problem asks for the current through a 9-ohm resistor in a circuit with resistors of 2 ohms, 4 ohms, 3 ohms, and 9 ohms connected to an 8-V source. The second problem seeks the voltage across a 40-ohm resistor in a circuit with resistors of 20 ohms, 40 ohms, 60 ohms, and 80 ohms connected to a 100 V source. Participants note the differences between calculating current and voltage in these contexts.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss the relationship between voltage, current, and resistance, questioning how to determine the voltage drop across resistors and the current flowing through them. Some express uncertainty about the formulas needed and the types of circuits involved (series vs. parallel).

Discussion Status

There is an ongoing exploration of the relevant concepts and formulas, with some participants suggesting that the original poster consult textbooks and examples for guidance. Multiple interpretations of the circuit configuration are being considered, and participants are encouraged to clarify their understanding of series and parallel circuits.

Contextual Notes

Participants mention the absence of a visual representation of the circuit, which may impact the understanding of the problem setup. There is also a reference to a study guide being used for exam preparation, indicating a focus on learning rather than immediate solutions.

  • #31
Good, so Req = 2+4+3+9 ohms = 18 ohms.

In a series circuit there is only one path for current to take so all of the current flows through all of the resistors. (Are you sure that you know what a series circuit looks like?)

Using Ohms law I=V/R you can calculate the current in your circuit. Use the voltage you were given and the resistance you calculated. What do you get?
 
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  • #32
8/18

If it's in parallel what's the formula for finding the total Resistance?
 
Last edited:
  • #33
if resistors are in parallel you want to know the formula for finding the total resistance...?

1/R_eq = 1/R1 + 1/R2 + ... + 1/Rn
 
  • #34
Ok, thank you.
 

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