Current Source with a resistor in series to power supply

Discussion in 'Power Electronics' started by BilalQureshi2, Sep 11, 2016.

  1. BilalQureshi2

    Thread Starter New Member

    Dec 24, 2014
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    I am wondering if a resistor in series to power supply V+ make a practical current source or not ?
     
  2. dannyf

    Well-Known Member

    Sep 13, 2015
    1,828
    365
    Yes. A current source is simply a voltage with infinite output impedance.
     
  3. OBW0549

    Well-Known Member

    Mar 2, 2015
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    890
    Yes. No. Maybe. It all depends on what you mean by "practical current source." If you'd give us more information on what you are trying to do, and what constitutes "practical" for your purposes, then perhaps we can give you an answer that makes some sense.
     
  4. BilalQureshi2

    Thread Starter New Member

    Dec 24, 2014
    7
    0
    I want to feed 1 mA current to temperature sensor PT1000.
     
  5. OBW0549

    Well-Known Member

    Mar 2, 2015
    1,328
    890
    If that's the case, then you need a precision current source; simply putting a resistor in series with the power supply voltage almost certainly WILL NOT deliver adequate accuracy and stability.

    Here are some links to information that may help you:

    Precision Interface for RTDs
    Solutions Search-- Resistance Thermal Device (RTD)
    Precision Temperature Sensing with RTD Circuits
    Images for "constant current source for RTD"
     
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