Re: 555 timer circuit

From: Paul (burtonfamily_at_dodo.com.au)
Date: 12/29/04 

Date: 29 Dec 2004 13:03:58 -0800

Bill Bowden wrote:
> burtonfamily@dodo.com.au wrote:
> > Hello,I made a simple astable 555 timer circuit the same as the one
> on
> > the 555 web site,but im having trouble working out the values of
the
> > two resistors and the capacitor so it will turn on for 3 minuts and
> off
> > for 5 minuts.Could someone please point me in the right direction
as
> i
> > found the data *** a bit confusing.thankyou in advance
>
> There is a 555 calculator on my site that will work out
> times based on components entered. But in operation
> the times will be a litte longer due to the capacitor
> leakage. Probably get about 10% additional time for 3 minutes
> calculated.
> http://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm
>
> -Bill

Thankyou for all your help,i`ll try all your ideas and see how i go,it
doesn`t worry me if it`s not real precise as im only using it to turn
on a bilge pump on a boat.I guess i`ll have to put a smoothing
capacitor in there somewhere to.cheers,
 Paul