Short cut tricks to find resistance of large/messed resistance's network.

In summary, these short cut tricks are not derived from experiments done by genius persons, but are derived from Kirchoff's laws of loops. Can you please tell me the proof or something like this for their tricks?
  • #1
vkash
318
1
Today our physics teacher teach us how to find resistance of a network of resistance that is messed to heavily(example all sides of a cube are resistance find resistance). Ok those are very good methods, but it seems that they are not result of experiments done by genius persons it seems that they are derived from Kirchoff's laws of loops. Can you please tell me the proof or something like this for their tricks these short cut tricks.
these short ct tricks are
(1)If in a network of resistances line joining terminals in an axis of symmetry then
(a) corresponding same point will carry same current.
(b) If network is folded about this axis of symmetry then equivalent resistance does not change.
(2)If in a network of resistances the perpendicular bisector of joining terminals is axis of symmetry then
(a) corresponding points will have same current but their directions will be different with respect to axis of
symmetry.
(b) If a resistance is lying on the axis of symmetry then it can removed without changing equivalent
resistance.
(c) all the points lying on this point will have same potential.
(3) If in network of resistances if all the resistances are became n times then net resistance will n times.
I don't ask him(teacher) for these proofs/derivations because like every time he will say " Proofs never come in examination so what's gain of learning those proofs or derivations."
After all i hope you will not reply so.

thanks for reading. make reply if you know anything about it.double thanks to repliers.
 
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  • #2
Does non of you know it's answer??
If their is any problem understanding question then tell me i will try to make it clear.
 
  • #3
vkash said:
Does non of you know it's answer??
If their is any problem understanding question then tell me i will try to make it clear.
I post it here bcz i thought there are some persons whichc will think on it. I think none of you think.Howeveri think a bit and want to share it with you.
explanation for
1(a) let us assume that there is different current in upward upper and lower part of circuit. Now just reverse the direction of the circuit i mean upper part in lower and lower in upper. So the current slowing in upper part will now the current in lower part and current flowing in lower part willl in upper part. BUT the circuit is same as it was before reversing. So here arise contradiction which can killed if and only current in upper and lower region will same.
1(b) still now i have no idea for this.
2(a) It is much similar to 1(a) but in this case we require to revert the direction of current. If we take current different then contradiction will arise which can be cured only by taking current similar.
2(b) It is derivative of 2(a)
2(c) doesn't get;
2(d) One more thing that i can't explain.

hey friends please help yar;Tell me something that how it can.
 
  • #4
(b) If a resistance is lying on the axis of symmetry then it can removed without changing equivalent
resistance.

Perhaps you should have another chat with your advisor?

Look at the following circuit and ask yourself if the equivalent resistance between A and B is unaffected by removing Rs.

go well
 

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  • #5
Studiot said:
Perhaps you should have another chat with your advisor?

Look at the following circuit and ask yourself if the equivalent resistance between A and B is unaffected by removing Rs.

go well
This is wheat stone bridge. It is not affected by Rs.But think this is not the way of explaining any thing. I mean 2*2=4 and2+2=4. It does not mean that * is same as +.
How you can explain all the phenomena by one example. It's particular case.
 

1. How can I quickly calculate the resistance of a large network of resistors?

One shortcut trick is to use the parallel and series combination formulas. Identify the resistors that are connected in parallel and use the formula 1/Rtotal = 1/R1 + 1/R2 + 1/R3... to find the equivalent resistance. Then, identify the resistors that are connected in series and add them together to find the total resistance.

2. Can I use shortcut tricks for networks with resistors of different values?

Yes, you can still use the parallel and series combination formulas. Just make sure to convert any values that are not in the same units before plugging them into the formulas.

3. Do these shortcut tricks work for complex networks with multiple branches?

Yes, the shortcut tricks can still be used for complex networks. It may take some practice and careful identification of parallel and series connections, but the formulas still apply.

4. Are there any other shortcuts or tricks for finding resistance in large networks?

Another helpful trick is to use the Delta-Wye transformation. This involves converting a delta (triangle) network into a wye (star) network, which can make calculations easier. There are also computer programs and software available that can quickly solve complex networks.

5. How accurate are these shortcut tricks compared to traditional methods of calculating resistance?

These shortcut tricks provide a close approximation of the actual resistance, but they may not be completely accurate. For more precise calculations, it is recommended to use traditional methods such as Kirchhoff's laws or Ohm's law.

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