PULSE GENERATOR/ CALIBRATION/ 555 TIMER /

Discussion in 'Homework Help' started by h9898, Jun 18, 2016.

  1. h9898

    Thread Starter New Member

    Jun 18, 2016
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    upload_2016-6-18_23-59-57.png
    I have been told to build the following circuit and adjust the POTS so that the pulse generators produce a 2:1 mark to space ratio and a 6KHz output.
    ok so i have managed to adjust the width to achieve that, however i now must adjust VR1 ( adjust graph height) so that that output is 5v. my question is why must the output be equal to 5V ?

    thanks
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    VR1 does not adjust the output voltage. Did you mean VR2?

    John
     
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  3. h9898

    Thread Starter New Member

    Jun 18, 2016
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    Yes i apologise, VR2 adjusted to about 53% gives a 5v output, ,,, also the iput battery is 9v not 5v.

    thanks
     
  4. jpanhalt

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    Jan 18, 2008
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    That makes sense now, because the 555 is not "rail-to-rail." That is, it can't drive its output completely to its supply levels.

    As for your question of "why 5 V," I assume it must be feeding something downstream that needs just 5 volts, not 7 or 8 volts. A microcontroller would be an example of one such device.

    John
     
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  5. h9898

    Thread Starter New Member

    Jun 18, 2016
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    thanks for your help
     
  6. JoeJester

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    Apr 26, 2005
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    The output is NOT variable, the output requires 2/3rd of the period to be high and 1/3rd to be low. The period remains constant (1/6 kHz). In your drawing, the frequency changes.

    You might want to revisit your schematic.

    Can you post a picture of the assignment's statement.
     
  7. jpanhalt

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    Jan 18, 2008
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    @JoeJester Check out Posts #2& #3. There was a misstatement in the original question.

    John
     
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