Square wave generator.

Discussion in 'General Electronics Chat' started by micktosin, Feb 14, 2013.

  1. micktosin

    Thread Starter New Member

    Mar 20, 2012
    19
    0
    Hi,
    Please i'm searching for a design that'll produce 10% duty cycle or less, hence 555 timer is not capable. Any suggestion would be greatly appreciated.

    Thanks.
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    You left out a lot of information, such as:
    Frequency range
    Frequency stability requirement
    Power supply voltage
    Output voltage and current capability
    Minimum and maximum duty cycle
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    A 555 timer can be wired for a very wide range of duty cycles; from a few percent to nearly continuous. You need to use one or more diodes to provide different current paths for charging and discharging of the timing capacitor. A switching diode (1N914, 1N4148) or Schottky diode (1N5817 thru 1N5819, BAT54, etc.) work well for this; standard rectifier diodes (like 1N400x, 1N540x, etc.) won't work very well past a few hundred Hz as their reverse recovery time (turn-off time) is very slow.
     
  4. #12

    Expert

    Nov 30, 2010
    16,262
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    In other words, a 555 will do this job, but you left out a lot of necessary information.
     
  5. SPQR

    Member

    Nov 4, 2011
    379
    48
    Do you ask this because stability can be changed by modifying the attached components?
    Or do you ask to determine if the 555 is able to have a stability of "X" and if not, you need to use a different strategy/chip?

    Thanks
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    My mind did not automatically gravitate to the 555. The question of stability is always relevant when an oscillator is called for.
     
  7. SPQR

    Member

    Nov 4, 2011
    379
    48
    Ok, there's the answer!
    What would you gravitate to?
     
  8. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    I'm waiting for an answer from the OP. He probably can't give us a quantitative answer, but he can tell us his application, and we can go from there.
     
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