Need help solving resistor network problems

[junior_J]

this isn't so much of a homework question . I am having trouble with identifying and calcultaing effective resistance for parallel or series connected resistors particularly ones that are very complex to even understand what's going on ... I did look through various websites and books looking for answers but ended up finding nothing ... my book listed 2 examples of the kind but these were poorly explained :(

this is not so much of a homework problem, but I've been having trouble solving these questions (2 days in a row )... are there any ways or say tips i could use to tackle these problems ? websites I've missed , books i might have to glance through ?? (but mainly helpful websites ...)

thanks in advance .
junior

 

[berkeman]

When you can, use series & parallel combinations of resistors to simplify the circuit. Once you're done with the simplifications, write the KCL (or KCL) equations for the nodes, and solve for the node voltages.

 

[junior_J]

the problems I am dealing with right now don't even mention emfs or pds ... they say something to the effect " Find the effective resistance between x and y " ... and in between x and y lies a jungle of resistors . I can't even comprehend how theyre put together ...

 

[berkeman]

Well, it's physical, so it's solvable. Can you post a copy of the drawing?

 

[junior_J]

there are many of these problems ... I just want to learn how to do this ... errm if ud do it for me Ill get off the hook pretty easy

Can u just tell me how ud go about solving these ? may be tips/pointers or something like that

teach a man how to fish blah blah proverb comes to mind :)

 

[junior_J]

... will i have to draw this one on mspaint ? really ... !
Im not jokin around ... i googled for these problems , nothin came up ...

 

[berkeman]

Sometimes you can use a symmetry in the problem to help out. Like with R-2R ladders used in DAC circuits, for example. Either you can simplify with parallel-series combinations, or use a symmetry, or you just have to brute force it with KCL. If all the resistors have the same value or related values, that generally helps with the symmetry arguments.

 

[junior_J]

My physics book doesn't even go as far as to properly describe how to do these ... Ill be damned if i ever open that book again !

anyways ur not getting through ... i have a thick skull !

thanks.