555 timer

[j medley]

I have built a 555 timer that when triggered provides an adjustable time period output.
At present when it is triggered any additional triggers do not reset the total time period.
It will only re trigger when the original time period has expired.
I would like to keep the time period going and then time out after the last trigger has occurred. Any suggestions.
thanks Jim

 

[KJ6EAD]

**broken link removed**

 

[ericgibbs]

hi Jim,

How is the 555 triggered.?

Is it capacitor coupled or direct coupling to pin 2.?

Whats the duration of the trigger and mono period.?

 

[j medley]

Thanks

Thanks very much KJ6EAD. My basic circuit is almost identical to the one in the link that you advised, I had tried various bits and pieces on the cap. connection to no avail. what a simple solution, I only need to add the pnp transistor.

Thanks again
Jim

 

[j medley]

thanks ericgibbs

Thank you for your interest.
Jim