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Dummy Load

Discussion in 'General Electronics Discussion' started by zemaj, Mar 10, 2011.

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  1. zemaj


    Mar 7, 2011
    Hi all,

    I want to design a dummy but I am having a problem finding a schematic for the project. If anyone could find it or have any good suggestion about this project please help. These are the requirements that should be included.

    Capable of operating between 3 - 30VDC, 400W, and from 0.01 to 20Amps.

    It also should operates in constant voltage, constant current, and constant resistance modes.

    Many thanks
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    400W is huge. You'll need the mother of all heatsinks.

    One method of doing this is to make a constant current sink. With a minimum voltage of 3V, it is certainly possible to do this with a self-powered design. However a simple option requires a sense resistor to drop about 0,6V at the full current. This is clearly not something that you can make variable -- although switched is an option.

    If you are happy to have the device powered from a separate source then you can have a fixed current sense resistor and use an op-amp to compare the voltage across this to some variable reference.

    You may want to check this.
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