load resistance,need clarification.

Discussion in 'General Electronics Chat' started by saraswathi.95, Jan 27, 2014.

  1. saraswathi.95

    Thread Starter Member

    Apr 11, 2013
    40
    0
    Hello,
    we often consider a resistance as a load,for any device in electrical terms ,
    why we need to consider it as resistance/impedance always,because power gets dissipated in resistor and it go waste as heat?
    even in antennas we consider its equivalent as a resistor.
     
  2. gabrielw6

    New Member

    Sep 21, 2013
    2
    0
    If we don't consider resistance or impedance, what else would we consider? Capacitance? The load you're putting into a power supply, somehow it will make some work. Put load's equivalent resistance is the method we found of saying this will do work. Not necessarily and relevant, the majority of apparatus you will connect to the power source has a resistance (even copper wires), and doesn't need to be a resistor, unless you're at a very very low temperature.

    Hope this helps.
     
  3. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,395
    497
    Eh?

    It is the other way around: we often consider a load as a resistance
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,042
    3,243
    The resistive part of the load absorbs the real power (the resistive part can be an actual resistor or appear in the load such as an antenna or motor). The reactance (cause by inductance and/or capacitance) is what determines the reactive part of the load (no real power dissipated).
     
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    even a perfectly matched antenna has IR lossses. and does cause heating. the mismatch impedance causes heating in the generator. a good match (non reactive) is still current, voltage, and resistance, will heat the load.
     
  6. saraswathi.95

    Thread Starter Member

    Apr 11, 2013
    40
    0
    Thank you,
    can any one tell me on what factors we consider load value and place it in all electrical equivalent circuit for analysis.(please do not explain all math stuff)
     
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