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  1. #1
    rx5
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    cd4538 pulse length

    Hi all,

    can anybody post link/scheme for a circuit .... like this:

    I input 1 sec positive pulse, and the output would be 1ms.....

    no using 555 IC.. if possible.... :)

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    cd4538 circuit

    You can use 74123 in place of 555 and on the positive edge of 1sec pulse, generate 1 ms pulse


    i hope i got your quote



    Quote Originally Posted by rx5
    Hi all,

    can anybody post link/scheme for a circuit .... like this:

    I input 1 sec positive pulse, and the output would be 1ms.....

    no using 555 IC.. if possible.... :)



    •   Alt16th May 2006, 11:35

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  3. #3
    rx5
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    1ms precision pulse pic c

    imjasmine

    but what if i input 500ms(0.5s) ?? would it still output 1ms??

    input range would be a min of 100ms to a max of 1000ms(1s) ....

    :)



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    rx5
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    pulse 1ms

    I think I got low power compatible chips...

    CD4528 and CD4538...

    still have to read the datasheets... :)

    Added after 1 hours 12 minutes:

    Hi again,

    Im having a hard time trying to USE/MAKE the circuit from the datasheet...

    heres a pic to help... Need it to be positive pulse triggered... input anywhere

    from 10ms to 1s.... but output should be 1ms.... anyone here could show me a

    circuit? :)

    BTW, is CD4528 compatible with 74123?

    sorry for bad drawing....


    [/img]



    •   Alt17th May 2006, 02:58

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  5. #5
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    1ms pulse

    The 74123 and the CD4528 are not compatibile but they are both timers and can do almost the same jobs ..
    For example, if you decide to use the 1/2 CD4528, connect input B to +V (also control input C has to be connected to +V) and connect input signal to the input A ..
    Each time the A-input will find a rising edge of the input signal, regardless of the length of the input pulse, the output pulse will be the same - 1ms, for instance - and will be detetermined by the external Rx and Cx (see data sheet at: http://www1.jaycar.com.au/images_uploaded/CD4528BC.PDF) ..

    Regards,
    IanP


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  6. #6
    rx5
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    74ls123 shema

    IanP,

    thanks.. :) so I guess I have to be using 100K for the Rx and .047uF for Cx..... for an output of 1ms....supply of 12V.



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    1ms pulse power

    Rx=100kΩ and Cx=47nF should generate output pulse pretty close to 1ms ..
    The pulse's length is almost independent of the power supply voltage, so if you have 12V or 15V or 5v it really doesn't matter ..

    Regards,
    IanP



  8. #8
    rx5
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    1ms pulse circuit

    ok IanP,

    got the circuit in breadboard.. working as I expected it to work.... :) thanks..

    BTW, I got CD4538 ... what I used... WAS much more better? (precision) than 4528 :)



  9. #9
    rx5
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    use cd4528

    hello IanP,

    can the CD4538 function also as a "gated" oscillator? like the input/output drawing shown bellow......If so, How?? :)



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