puzzle

[pebe]

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.

 

[kinjalgp]

The answer is 8.333 Ohms

MERRY CHRISTMAS to all Forum Members!

 

[bogdanfirst]

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.....

 

[pebe]

Bang on correct, both of you.

Anyone any similar puzzles I can do over Xmas?

 

[kinjalgp]

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

 

[bogdanfirst]

try this, all th segments have the value R

 

[bogdanfirst]

how can i send a pic?

 

[bogdanfirst]

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

 

[pebe]

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

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

 

[kinjalgp]

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

 

[pebe]

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

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

 

[bogdanfirst]

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....

 

[bogdanfirst]

**broken link removed**

 

[kinjalgp]

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 **broken link removed**

 

[Phasor]

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

 

[kinjalgp]

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.
**broken link removed**

 

[bogdanfirst]

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)

 

[bogdanfirst]

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

 

[kinjalgp]

Correct 500 Ohm is the right answer.

 

[pebe]

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

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