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Homework Help: Electronics - Designing a ciruit

  1. Feb 21, 2007 #1


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    1. The problem statement, all variables and given/known data

    Given an ideal power supply of 15 V and a load of 5 kilo ohms, design a circuit using 2 resistors in which the current flowing through the load is close to 2mA

    2. Relevant equations

    None given (I'm assuming V=IR)

    3. The attempt at a solution

    I'm a bit confused with this one, I understand that maybe I could have 2 resistors of 3.75 kilo ohms each to cause the current to me 2mA, but I'm unsure of what role the '5 kilo ohm load' has.

    Can anyone explain to me what this load is and what role it plays? I can't see it being internal resistance due to the power supply being 'ideal'.

  2. jcsd
  3. Feb 21, 2007 #2


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    Homework Helper

    A load could be a bunch of things, say a speaker or a lightbulb or an appliance. They consume electrical energy and can dissipate it as sound, light or heat...whatever the case may be. I believe you need to consider the resistance of the load in your design.
  4. Feb 21, 2007 #3


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    So basically I could just have 2 resistors in series with a total resistance of 2.5 kilo ohms and the 5 k'ohm load.

    Thus, using I = v/R I'd get the 2mA that is expected!

    Does that make sense??
  5. Feb 21, 2007 #4


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    Staff: Mentor

    Thread moved from Advanced Physics to Intro Physics.

    kel, yes your answer is correct. By placing the 2.5 kOhms in series with the 5.0 kOhms, that will give you a 2mA current supplied by the 15V power supply.
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