# puzzle

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by pebe, Dec 23, 2002.

1. ### pebeMember

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Just a little light hearted puzzle to keep the grey matter active over Christmas when you are not busy with the soldering iron!

A plastic cube has a 10ohm resistor laid along each of its 12 edges. At each corner the ends of the three meeting resistors are connected together.

What is the resistance between two furthest corners? :?

Happy Xmas to everyone.

2. ### kinjalgpActive Member

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The answer is 8.333 Ohms

MERRY CHRISTMAS to all Forum Members!

3. ### bogdanfirstNew Member

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hey, good question .....
i used to do theses kind of problems at physics last year...
it's not hard to calculate...
first u resuce the cube to a pyramid, then o use the tranfiguartion from star to triangle and all u obtain is a simple group of paralel and series resistors..
i don't know if the value is 8.333 ohms, i dont have time to calculate...
but what i can tell u is that if u make the schematic and use a simulation progrma many would give u a wrog answer.....

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5. ### pebeMember

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Bang on correct, both of you.

Anyone any similar puzzles I can do over Xmas?

6. ### kinjalgpActive Member

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Ok Pebe try same puzzle with resistor value of 330 Ohm! 8)

7. ### bogdanfirstNew Member

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try this, all th segments have the value R

8. ### bogdanfirstNew Member

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how can i send a pic?

9. ### bogdanfirstNew Member

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so stupid i was....
here's another puzzle.all the segmants have the value R, find the value between the nodes[/list]

10. ### pebeMember

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Without a calculator to hand - so done in my head, I think it's 275ohms.

11. ### kinjalgpActive Member

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CORRECT
It was easy ! For 10Ohm it was 8.33 so for 330 Ohm it will be 330*8.33/10 = 274.89 ~ 275 Ohms

12. ### pebeMember

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I can't see what the "[/list]" is. Can you describe which nodes?

13. ### bogdanfirstNew Member

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i cant post a picture of the schematic.....
i used cut+imc here and it still doesnt work....
somebody tell me how to place a picture in tthe answer....

14. ### bogdanfirstNew Member

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15. ### kinjalgpActive Member

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You have to first store the picture on internet. You can store it on free web space like geocities. The type the URL of your file between "img" tags.
Like

16. ### PhasorMember

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I might just mention that this is certainly not a new puzzle. I have seen it published in ETI, about 1974.

17. ### kinjalgpActive Member

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Ok lets see if some one can find what the equivalent resistance be between terminals A and B. I want calculation steps and not only final answer . Terminal B is in the lower right corner which is not visible in the schematic.

18. ### bogdanfirstNew Member

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u wanta calculatons...
ok
from what i ses there is a square and 2 diagonals....the 2 other corners apart from A and B are at the same potential so there is no current flawing drom the resistance that unites them can be eliminated.....
now, a square and a diagonal from a to b....
unite the points with the same potential and u get a triangle....
turn the triangle in a star and trough one of the resistors is not flawing current, so there are only 2 250 ohm resistors...
so the value is 500 ohms?
(p.s. i mistake most of the time when it comes to mathematical calculations, so this might not be an exception)

19. ### bogdanfirstNew Member

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another puzzle....
try the one above with capacitors......1uF

20. ### kinjalgpActive Member

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Correct 500 Ohm is the right answer.

21. ### pebeMember

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Resistance = infinite (or as determined by the leakage)
Capacity = 2uF