Negative edge trig device - Multisim

Thread Starter

Philz

Joined Dec 2, 2007
3
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
 

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hgmjr

Joined Jan 28, 2005
9,029
Have you considered using an inverter in series with the clock signal? Or does that introduce other complications?

hgmjr
 

GS3

Joined Sep 21, 2007
408
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
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.
 

Thread Starter

Philz

Joined Dec 2, 2007
3
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.
 

Thread Starter

Philz

Joined Dec 2, 2007
3
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.
 

GS3

Joined Sep 21, 2007
408
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.
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?
 

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Ron H

Joined Apr 14, 2005
7,014
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?
Maybe he is not including an RC differentiator in front of pin 2. See the datasheet (or GS3's schematic).
 
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