Equivalent Resistance: Unravel the Mystery

In summary, the conversation revolved around the mathematical concept of an infinite resistor network, specifically the process of measuring the voltage across each resistor to determine the overall value. The conversation also touched on the genius of a related comic and the use of similar concepts in physics exams.
  • #1
martix
168
3
http://xkcd.com/356/
I'm clueless, yet curious.
 
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  • #2
who knows, who cares, its unmeasureable :)

its just a cartoon, enjoy the joke on the physicist ;)

Dave
 
  • #3
Well if you really want to know, build it. You don't need to build it to infinity though, just 10 resistors or so in each direction should get you pretty close. Then measure the voltage across each resistor to see how the network carries it.
 
  • #4
It has to approach some value and certainly has to be mathematically expressible.

On a side note, the comic is pure genius. :D Guess I got sniped as too... well, not that I'm dead, but I certainly caught some flak since it's 5AM and I'm still actively waiting on a reply here.
 
  • #5
yeah, the trick is find the pattern. see if you can make an infinite series out of it and see if it converges. something along those lines. and I'm sure it does, because if you measure between two points on a metal sheet, it won't be zero no matter how big the sheet gets. but my head hurts, and I'm lazy.

we got stuff similar on physics exams years ago, but smaller, say between the diagonals of a cube where the edges are resistors and the corners nodes. there it becomes a symmetry trick. or, mesh/nodal analysis when you get to circuits courses.
 
  • #6
Already discussed in this thread: [thread]206096[/thread] (now locked 'cause it's too old).
 
  • #7
^ugly.
 

Related to Equivalent Resistance: Unravel the Mystery

1. What is equivalent resistance?

Equivalent resistance is the total resistance that a circuit experiences when multiple resistors are connected in series or parallel. It is a simplified representation of the circuit, as if all the resistors were replaced by one resistor with the same resistance.

2. How do you calculate equivalent resistance for resistors in series?

To calculate equivalent resistance for resistors in series, you simply add up the individual resistances. For example, if you have three resistors with values of 10 ohms, 20 ohms, and 30 ohms connected in series, the equivalent resistance would be 10 + 20 + 30 = 60 ohms.

3. How do you calculate equivalent resistance for resistors in parallel?

To calculate equivalent resistance for resistors in parallel, you use the formula: 1/Req = 1/R1 + 1/R2 + 1/R3 + ... where Req is the equivalent resistance and R1, R2, R3, etc. are the individual resistances. For example, if you have two resistors with values of 10 ohms and 20 ohms connected in parallel, the equivalent resistance would be 1/(1/10 + 1/20) = 6.67 ohms.

4. What is the difference between series and parallel circuits in terms of equivalent resistance?

In series circuits, the equivalent resistance is always greater than the individual resistances, as adding more resistors increases the total resistance. In parallel circuits, the equivalent resistance is always less than the individual resistances, as there are multiple paths for current to flow, reducing the overall resistance.

5. How does equivalent resistance affect the overall current and voltage in a circuit?

According to Ohm's Law, V=IR, where V is voltage, I is current, and R is resistance. Therefore, as equivalent resistance increases, the current decreases, and as equivalent resistance decreases, the current increases. The voltage remains the same throughout the circuit, as it is determined by the power source.

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