Calculating equivalent resistance in the following circuit

Discussion in 'Homework Help' started by natrawrs, Aug 10, 2010.

  1. natrawrs

    Thread Starter New Member

    Aug 10, 2010
    Hi everyone,
    I was given the following circuit and i have to work out the equivalent resistance in the circuit, given that each resistor has a resistance of 123456789 ohm. I havent learned much about equivalent resistance, I hope you could teach me some basics and steps on how to work it out. Thanks!
  2. JDT

    Well-Known Member

    Feb 12, 2009
    Start with assuming that a voltage is applied across the corners and therefore a current flows from A to B.

    Note that a number of nodes in the array will have equal voltages and can be connected together without changing the operation. The circuit then becomes an array of paralleled resistors.

    In fact there will be 2 paralleled resistors in series with 4 paralleled resistors in series with 6 ... (do you see where I'm going?).

    Work it out assuming each resistor is 1 ohm then scale by 123456789.

    Actually it's easy!
  3. The Electrician

    AAC Fanatic!

    Oct 9, 2007
    Be very careful with assumptions about this. Things are not what you think.

    This is not quite true.

    It's not as easy as you think.

    See this thread:
  4. JDT

    Well-Known Member

    Feb 12, 2009
    Sorry, this comes of replying very quickly while I should be doing something else (working)!

    But, I think I am right in saying that that points C have the same potential and can be connected together, and points D, and points E. Once you have done that resistors x and y can be replaced with a single resistor.

    Then work it out with all resistors 1Ω and scale.