max power transfer theorem

Discussion in 'Homework Help' started by haditya, Nov 19, 2004.

  1. haditya

    Thread Starter Senior Member

    Jan 19, 2004
    220
    0
    the other day we were conductiin expt for verification of max power transfer theorem.
    we ogt the results more or less accurately but i hav a few doubts...
    max power is said 2 be transfered from source to load if Ri=RL
    at this condition efiiciency is 50%
    on increasing Rl greater than Ri...we found that efficiency increases :blink: :blink: :eek:
    theoriticall it becomes 100% for Ri=0...which is practically impossible..
    my question is how can efiiciency be greater then 50%...if max power is transfered at 50% efficiency :blink:
     
  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    It's more accurate to say that maximum energy is transferred when the *output* resistance Ro=RL, because the power source has an output resistance, and the load has an input resistance.

    When Ro=0, it's the same as wiring a lamp direct to the mains supply, and all available power can be taken by the lamp.

    But the max power Ro=RL concept is applicable when you are faced with a power source that has a finite Ro, and it is necessary to match the load so that it can take maximum power.
     
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