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Homework Help: Design voltage divider circuit

  1. Mar 22, 2013 #1
    1. The problem statement, all variables and given/known data

    The memory components in a personal computer require voltages of -12 V, 4 V and 12 V all with respect to a common reference terminal (you can assume this to be the ground). Design a circuit to achieve this if the total power supplied to the divider circuit is 80 W and the supply voltage is 24 V.

    3. The attempt at a solution

    its simple to make the voltage divider for the positive terminal voltages, but im not sure, mathematically, how to include a negative terminal.

    Ive been placing a resistor between the negative terminal on the source and the ground but whatever resistor i put in there changes the rest.

    i suppose my question is
    How do you achieve negative voltages from a one sourced voltage divider?

  2. jcsd
  3. Mar 22, 2013 #2

    rude man

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    Think switching regulators!
  4. Mar 24, 2013 #3


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    Is that really the entire question?

    You would normally need to know the power required for each rail. It's trivial to make a 4V rail if you only need a few uA from it.

    The problem doesn't appear to stop you making the +12 and -12 by "center tapping" the 24V ??
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