Circuit Problem: How Many Ways to Light All the Bulbs?

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SUMMARY

The discussion centers on calculating the number of ways to connect a battery (B) to a series of distinct bulbs (A1, A2, ..., An) without forming loops, focusing on tree and series configurations. Participants agree that the number of arrangements increases rapidly with the number of bulbs, with formulas such as (n+1)!/2 for series connections being discussed. The conversation highlights the mathematical nature of the problem, emphasizing graph theory and topological inequivalence in circuit arrangements. Ultimately, the complexity of the problem grows significantly as the number of bulbs increases, necessitating a systematic approach to find a general formula.

PREREQUISITES
  • Understanding of basic circuit theory and components (battery, bulbs)
  • Familiarity with graph theory concepts and topological equivalence
  • Knowledge of permutations and combinations in mathematics
  • Ability to visualize circuit configurations and their mathematical implications
NEXT STEPS
  • Research "Graph Theory and Circuit Design" to understand topological equivalence
  • Study "Permutations and Combinations" to apply mathematical principles to circuit arrangements
  • Explore "Tree Structures in Graph Theory" for insights on circuit configurations
  • Investigate "Mathematical Formulations for Circuit Arrangements" to derive general formulas
USEFUL FOR

Mathematicians, electrical engineers, and students interested in combinatorial problems and circuit design will benefit from this discussion, particularly those exploring the intersection of graph theory and electrical circuits.

  • #31
see my diagram when it is ready...hopefully it will convey what I mean before.

case I and II are effectively the same after redrawing (unless you have some weird rules governing your system)
 

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  • #32
No, it is not like that. You can not stretch the wire that way. Imagine, the bulbs are far from each other, so in the case I, you connect from B to A1 and then from A1 to A2. It is completely different from your circuit.
You have created one more node in your drawing. The requirement here is that the wire can only be connected to the battery or a certain bulb, not to common node.
 
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  • #33
tell me how you can connect two wires to one terminal without "making one more node". My point is coming from elementary circuit theory point of view.. if you know what I mean. you want to connect two wires to the same terminal of the device, the "new node" that you have created is the point where the two wires and the terminal meet, before connection there is no (essential) node. You have a (essential, 3-way) node after connection because conservation of "stuff" holds at that junction (eg. KCL)...
you said that wires can only be connected to battery/device... true... but nothing forbids current to go from A1 to A2 without entering B in between, so there will be a direct link beween A1 and A2 even when u have B in between. This is the effect of connecting two wires together a same point.

I brought this issue up because there may be problems in defining what are equivalents and what are not when you have tree structure that may have some rotational symmetry in them.
 

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