Resistor calculations

Discussion in 'General Electronics Chat' started by Webby, Oct 19, 2008.

  1. Webby

    Thread Starter Active Member

    Jun 15, 2008
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    0
    Hi, with two resistors in parrallel circuit of the same value the equation

    R1 X R2 divided by R1 + R2 = Total resistance

    does this equation still apply if the resistors are of different value?
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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  3. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Yes, but it applies only for two resistors in parallel. If you have more than two use this formula:

    Requivalent=1/(1/R1+1/R2........+1/Rn)
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    That same trick can be used to tweak standard resistors to astandard values. Given 3 resistors you can get pretty close to any value you choose, as long as your meter is accurate and the resistors don't drift.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Here is an online calculator that's quite handy for determining combinations of two resistors in series or parallel to arrive at an equivalent resistance:
    http://www.qsl.net/in3otd/parallr.html
     
  6. Asad Ullah Muhammad

    New Member

    Oct 20, 2008
    6
    0
    YES YOU CAN DO
     
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