PIC powered by capacitor for 0,5 second


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  1. #1
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    It's a gadget for a car.

    I'll use a 7805 to make a clean +5VDC.
    Roger

  2. #2
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    This is what happens with 1000 μF and a load of 1.62 mA.



    Luciano

  3. #3
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    I suppose that a 4700 is the minimum capacitor to use. There are .5 and 1 Farad capacitors in low voltage now available to power RTC's instead of coin batteries. Why not use one?

    Take a look at http://catalog.digikey.com/scripts/p...?name=P6955-ND

    Ioannis

    P.S. By the way, nice instrument Luciano!
    Last edited by Ioannis; - 23rd August 2007 at 10:17.

  4. #4
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    Quote Originally Posted by Luciano View Post
    This is what happens with 1000 μF and a load of 1.62 mA.



    Luciano
    Hi, Luciano

    Nice to see you back here !

    mmmmmmh, By the way ....

    You gave the PEAK current ... as it decreases with power Voltage.

    A JFET could have been a better current drain than the 2.7k.

    Were nice holidays, weren't ??? You're not totally back it seems ... LOL !!!

    Best Regards
    Alain
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    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
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  5. #5
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    Hello Alain,

    Could you give me some more details about how to connect the transistor and even why this would be a better choice please?
    Roger

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    Hi,

    If you have not done so already try turning off the brown out detect at the programming stage, this will stop the pic from resetting as the voltage drops. With a 2200uF cap that should work fine

    Regards
    Bob...
    Last edited by BobEdge; - 23rd August 2007 at 15:27.

  7. #7
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    Hi Alain,

    Thank you for appreciating my midnight engineering!

    Best regards,

    Luciano

  8. #8
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    Hi Roger,

    Try that:



    Best regards,

    Luciano

    EDIT: The Brown-out Detect Voltage (BVDD) is 2.025 — 2.175 V.
    Try first with the internal Brown-out Detector enabled.
    Last edited by Luciano; - 23rd August 2007 at 22:21.

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