Current through a resistor.

In summary, the conversation is about a student struggling with a physics problem involving Kirchhoff's Laws. The student provides a link to a circuit and the given values for the components. The question is to determine the current through R1. After attempting to solve the problem, the student provides a solution of Req=485400 ohms and a total current of 1.23 x 10-5.
  • #1
uselessprog
1
0
Okay, I've been trying to study for my physics final and I've been stuck on this one for a few hours now...it's driving me crazy. There must be a flaw in my understanding of Kirchhoff's Laws.
A link to the circuit can be found here -> http://img410.imageshack.us/img410/7798/resist.jpg [Broken]

Homework Statement



The battery voltage is 6 V.
C1 = 1.8000000000000002 * 10^-8 F C2 = 1.5000000000000002 * 10^-8 F
C3 = 1.1000000000000001 * 10^-8 F
R1 = 270000.0 ohms R2 = 560000.0 ohms R3 = 110000.0 ohms
R4 = 120000.0 ohms R5 = 390000.0 ohms R6 = 180000.0 ohms
R7 = 680000.0 ohms
What is the current through R1?


2. The attempt at a solution

R12 = 830000 ohms
R123 =97127 ohms
R67 = 860000 ohms
R567 =268320 ohms
Req= 485400 ohms
Total current = 1.23 x 10-5
 
Last edited by a moderator:
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  • #2
Welcome to PF!

Hi uselessprog! Welcome to PF! :wink:
uselessprog said:
Req= 485400 ohms
Total current = 1.23 x 10-5

485400 Ω looks right :smile:

but how did you get 1.23 x 10-5?
 
  • #3
A
Current through R1 = 0.0000254 A

Dear student,

First of all, it's great that you are trying to understand Kirchhoff's Laws and their application in circuit analysis. It's a fundamental concept in electrical engineering and physics, so it's important to have a strong understanding of it.

Now, let's take a look at the circuit you have provided. From the given values, we can calculate the total resistance of the circuit as 485400 ohms, which is correct. However, I believe there is a slight mistake in your calculation of the total current. The correct value should be 1.24 x 10^-5 A, which is equivalent to 0.0000124 A.

To find the current through R1, we can use the formula V=IR, where V is the battery voltage (6V in this case), I is the current through the resistor, and R is the resistance of the resistor. Rearranging the formula, we get I=V/R. Substituting the values, we get I= 6/270000, which gives us a current of 2.22 x 10^-5 A, or 0.0000222 A.

I hope this helps clarify your understanding of Kirchhoff's Laws and calculating current through resistors. Keep practicing and don't get discouraged, you'll get the hang of it soon! Good luck on your final exam.
 

1. What is current through a resistor?

Current through a resistor is the flow of electric charge, measured in amperes, passing through a resistor. It is the rate at which electric charges move through the resistor.

2. How is current through a resistor calculated?

Current through a resistor can be calculated using Ohm's Law, which states that current (I) equals voltage (V) divided by resistance (R). This is represented by the equation I = V/R.

3. What factors affect the current through a resistor?

The current through a resistor is primarily affected by the voltage applied across it and the resistance of the resistor. Other factors that can impact current include temperature, material properties of the resistor, and the presence of other components in the circuit.

4. How does current through a resistor impact the circuit?

Current through a resistor can impact the circuit in several ways. It can cause a voltage drop across the resistor, which can affect the voltage and current in other components in the circuit. It can also generate heat, which can potentially damage the resistor or other components.

5. How can current through a resistor be controlled?

Current through a resistor can be controlled by changing the voltage supplied to the circuit or by adjusting the resistance of the resistor. It can also be controlled by using other circuit elements, such as diodes or transistors, to regulate the flow of current.

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