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help about ADC0808 - DAC0808

Discussion in 'Homework Help' started by Gantronics, Dec 18, 2010.

  1. Gantronics

    Gantronics New Member

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    In you heart ...^_^...
    Hello
    I need a little help about a mini project (ADC then DAC) using ADC0808 then DAC0808...
    I connected every thing (just as in the picture) >>>part 1 ADC0808 ...
    [​IMG]
    but I have been told that I need clock 550 KHz (some one told me It will work from 500 to 650 KHz)...
    can I generate it with NE555 ?
    And what is the "Crystal" & "frequency divider" ?

    Drawing make an easy understanding for me (If possible) ...^_^...
    Thanks...
     
  2. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Look at this image for the input clocking range.

    A 555 timer configured as a astable would be ok for this application, say at 500kHz

    You dont need a crystal or dividers.
     

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  3. Gantronics

    Gantronics New Member

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    Thanks...

    But I cant see the picture for some-why , can you upload it again?...^_^...
    The frequency of 555 f=1/T=1/0.7(RA+2RB)C , can I use a ceramic capacitor with 555 or it must be electrolytic one?...
     
  4. dave

    Dave New Member

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  5. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Look at this link.
    http://www.electro-tech-online.com/blogs/ericgibbs/125-simple-7555-cmos-timer-calculator-v1-2.html

    I would choose a clock frequency of between 100kHz and 500kHz.
     

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