power versus resistance

Discussion in 'Physics' started by buseh, Feb 9, 2007.

  1. buseh

    Thread Starter New Member

    Feb 9, 2007
    1
    0
    i need some help with graph of power versus load of resistance when there is a source of emf with internal resistance. maximum and min power?? how to do this??
     
  2. Papabravo

    Expert

    Feb 24, 2006
    9,903
    1,723
    Twinkle twinkle little star
    Power's equal I squared R
     
  3. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    143
    Further to Papabravo's answer, you need to compute the power values for each value of resistance you have. For this you need to assume constant current and voltage to get the plot for Power Vs Resistance.

    So for P = (I^2)*R

    I = some constant value

    And you can calculate P for different values of R. Plot resistance on the x-axis and power on the y-axis.

    Dave
     
  4. recca02

    Senior Member

    Apr 2, 2007
    1,211
    0
    when there is a emf source with internal source try making a eq circuit and
    place internal resistance in series with emf source use thevenin's theorem
    to get simplified circuit in case of complex circuits, it really isnt that hard,
    one important clue for max power the load impedance must equal the circuit's
    thevenin's eq ckt impedance.
     
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