From: "Michael A. Terrell"
Subject: Re: 555 Clock Circuit
Date: Tue, 17 Sep 2002 14:14:38 -0400
Organization: I'm trying!
X-Mailer: Mozilla 4.61 [en]C-CCK-MCD (Win95; U)
> Why not try to source out a Motorola MM5369 which is a 60 Hz timebase? It
> can be configured to be a 1hz timebase as well if you use a couple of
> 4017 as dividers. Perfect for building a clock. It uses a 3.579545 Mhz
> crystal (tv colour crystal) for accurate timing. If you are interested in
> the info I have (RS - Forrest M. Mims III circa 1982), let me know via E-
> Mail and I'll send you a PDF of the timebase info.
> - Tim -
> In article ,
> firstname.lastname@example.org says...
> > James wrote:
> > > I'm very new to electronics, and just wanted to start with something
> > >small. I was thinking of constructing a binary clock, and have drawn out
> > >my design. I was just wondering what to use for the impulse to my 4-bit
> > >binary counters. I was thinking of using a 555 IC set to 1hz. Is it
> > >possible to create a clock with the 555 IC, or will it never be accurate
> > >enough with my cheap materials to produce an Impulse that doesn't lose
> > >time? Is there any other device that I could use? If it is possible, I
> > >would like to use the 555, as I already have those on hand and available.
> > If you use the circuit shown at
> > http://www.terrypin.dial.pipex.com/Images/555Astable+Driver.gif
> > with Ct = 1uF, R1 = 1k, and R2 = a series combination of 470k plus a
> > 1M preset, then you should be able to adjust the frequency of your
> > clock to 1 Hz with better than 1% accuracy (through a range of about
> > 0.6 to 2.0 secs per cycle).
> > Terry Pinnell
> > Hobbyist, West Sussex, UK
MM5369 WAS a National Semiconductor part, not Motorola. It has been
out of production since 06/03/97. A datasheet is still available at:
http://www.national.com/pf/MM/MM5369.html You have to watch surplus
parts. There are different versions, with different output
frequencies. The datasheet states that the MM5369AA version is the
An old fart since August 5th, 2002!
Michael A. Terrell
Check out my web site and tell me what you think.
I'm up to 160 pages, and still working on it.