Finding Equivalent Resistance in Resistor Network - Can You Help?

In summary, the speaker is seeking assistance with finding the equivalent resistance between points A and B on a circuit. They initially make a mistake by assuming that R5 and R6 are in parallel, but are corrected and advised to use Kirchoff's Law to solve the problem. With some guidance, they correctly determine that R4 and R3 are in parallel, and this equivalent resistance is then in parallel with R6, resulting in an answer of 4k. The speaker thanks others for their help and acknowledges that it makes more sense now.
  • #1
kdinser
337
2
Can someone tell me where I'm going wrong here?
I'm uploading a jpeg of the circuit, I'm supposed to find the equivalent resistance between A and B.

To me, it looks like R5 and R6 are in parallel and forming Rp56. From there I'm assuming that Rp56 would be in parallel with R3 and then that whole top part (R5, R6, and R3) would be in series with R4.

Can someone point out where I'm making my error? I'm coming up with a total resistance of 5k and the answer should be 4k.
 

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  • #2
kdinser said:
To me, it looks like R5 and R6 are in parallel and forming Rp56. From there I'm assuming that Rp56 would be in parallel with R3
This is incorrect because the chain is more complex due to the different interconnecting wires. What you need to do is to apply Kirchoff's Law. Do you know this procedure ? You basically apply charge conservation and energy conservation on each subchain. So, the first thing to do is to detect each subchain (you have three such chaines in your case).

marlon
 
  • #3
kdinser said:
To me, it looks like R5 and R6 are in parallel and forming Rp56. From there I'm assuming that Rp56 would be in parallel with R3 and then that whole top part (R5, R6, and R3) would be in series with R4.

To be in parallel, the two resistors have to have the same potentials at BOTH ends, which means both their ends touch each other. Here 5 and 6 only touch at one end. Shorten all the wires and redraw the circuit without wires and see which resistors touch at both ends. I did it and came up with 4k as the answer.
 
  • #4
I think I have it, at least I'm coming up with the correct answer now.

Going back to the original diagram, R4 and R3 are in parallel giving a resistance of 2k which is in series with R5. This equivalent resistance is then in parallel with R6.

Sound right? Thanks for the help guys.

Oh, and thanks for not just spewing out the answer, it makes a lot more sense now.

Keith
 
  • #5
kdinser said:
Going back to the original diagram, R4 and R3 are in parallel giving a resistance of 2k which is in series with R5. This equivalent resistance is then in parallel with R6.

Sound right?

That's the way I got it.
 

Related to Finding Equivalent Resistance in Resistor Network - Can You Help?

1. How do I find the equivalent resistance in a resistor network?

To find the equivalent resistance in a resistor network, you can use the following formula:
Req = R1 + R2 + R3 + ... + Rn
where R1, R2, R3, and so on represent the resistances of each resistor in the network. This formula works for both series and parallel circuits.

2. Can I use Ohm's Law to find the equivalent resistance?

Yes, you can use Ohm's Law (V=IR) to find the equivalent resistance in a resistor network. Simply apply the formula V=IR to the entire network, where V is the total voltage, I is the total current, and R is the equivalent resistance.

3. What is the difference between series and parallel circuits?

In a series circuit, the resistors are connected end to end, so the current flows through each resistor in succession. The equivalent resistance in a series circuit is the sum of all the resistances. In a parallel circuit, the resistors are connected side by side, so the current is divided among the different branches. The equivalent resistance in a parallel circuit is always less than the smallest individual resistance.

4. Can I use a multimeter to find the equivalent resistance?

Yes, you can use a multimeter to find the equivalent resistance in a resistor network. Set the multimeter to the resistance measurement mode (often denoted by the Greek letter omega), and then measure the resistance across the entire network. This will give you the equivalent resistance.

5. Why is finding equivalent resistance important in circuit analysis?

Finding equivalent resistance is important in circuit analysis because it allows us to simplify complex circuits into a single resistor, making it easier to calculate current and voltage in the circuit. It also helps us understand the overall behavior of the circuit and how different components affect its performance.

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