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Resistors and circuit requirements

  1. May 17, 2009 #1
    1. A student needs a 5Ω and 10Ω resistor for a circuit, but she only has a dozen 20Ω resistors. Does she need to buy new resistors or can she meet the circuits requirements with the resistors that she has? Explain (be specific!).

    2. I honestly don't know any equation to use...



    3. What I'm thinking is that the girl can make a circuit with 2 parallel circuits like this one in this picture below. And by finding the req for each one, one would be 5Ω and the other would be 10Ω

    parallelresistor.jpg
     
    Last edited: May 17, 2009
  2. jcsd
  3. May 17, 2009 #2
    You are on the right track. It only remains to work out how you make each of the required resistors from 20 ohm values.

    A Hint: For example if you put 2 x 100 ohms in parallel you get 50 ohms.

    So how many 20 ohms in parallel would make 10 ohms? Once you get a handle on that idea, it should be a simple matter to work out to get 5 ohms (1/4 of 20).
     
  4. May 17, 2009 #3
    alright thanks alot overt26
     
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