Negative edge trig device - Multisim

Discussion in 'The Projects Forum' started by Philz, Dec 2, 2007.

  1. Philz

    Thread Starter New Member

    Dec 2, 2007
    3
    0
    Need a simple negative edge triggered device or circuit that i can insert into a multisim simulation. (So the device needs to be available on there.)

    The attached diagram shows what output waveform i require and the part of the circuit where its needed.

    Any Help or Advice would be Appreciated

    Thanks Philz
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    Have you considered using an inverter in series with the clock signal? Or does that introduce other complications?

    hgmjr
     
  3. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    I am not sure I undertand. You want a negative edge triggered monostable? Anything wrong with using a 555 for that? You know, specially since the rest of the circuit is already full of 555 monostables. Am I missing something?

    Aside: Using a graphic most of which is empty white space is a waste. Using JPG is further waste and just degrades it. I recommend you use PNG and trim it.
     
  4. Philz

    Thread Starter New Member

    Dec 2, 2007
    3
    0
    Yes,
    It adds complications because I thought of putting an inverter on the output of a single monostable but this makes the output high befroe the trigger.
    The wave form i need is low before trigger, low for time (t) and then high then latched high indefinatly.

    thanks Philz.
     
  5. Philz

    Thread Starter New Member

    Dec 2, 2007
    3
    0
    Do you know a circuit diagram or website address for a negative edge triggered monostable bearing in mind i would like any components used to be simulated in multi-sim.

    thanks Philz.
     
  6. hgmjr

    Moderator

    Jan 28, 2005
    9,030
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    Have you looked into Flip-Flops such as J/K, SET/RESET, or D-type?

    hgmjr
     
  7. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    Again, I'm not sure I follow you. The 555 is negative edge triggered like you are showing in your diagram. Why don't you just put anothr one in there? Maybe I am completely misundertanding the problem but it seems to me a 555 in there would do exactly what you want. Or what am I missing?
     
  8. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    Maybe he is not including an RC differentiator in front of pin 2. See the datasheet (or GS3's schematic).
     
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