Subject: Re: Timer circuit for relay?
Date: Fri, 04 Oct 2002 19:43:45 +0200
Organization: XS4ALL Internet BV
References: <0001HW.B9BF07130030FEA7165FEAC0@news.covad.net> <firstname.lastname@example.org> <0001HW.B9C30A9400B47E5B165FEAC0@news.covad.net>
NNTP-Posting-Date: 4 Oct 2002 17:45:38 GMT
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On Fri, 4 Oct 2002 9:06:28 -0700, DaveC wrote:
>On Wed, 2 Oct 2002 7:40:52 -0700, René - wrote
>(in message <email@example.com>):
>OK, I've checked out the decade counters (4020, 4040, 4060). I could run one
>of these with the output from a slow (~1 hz) 555. I thought about making the
>counter an oscillator (RC components, according to the data sheet, will drive
>it), but I don't know about running a CMOS device at this slow rate...
>What does the NG collective think? Am I better off driving the counter with
>the output from an adjustable 1 hz 555, or making the counter an oscillator
>using RC components? Is one more stable than the other?
The 4060 contains clock *and* divider, so no need to use the horrible
(sorry - it's a personal Don Quichotte thing - I like to kick 555's
because almost always there is a better and simpler solution - e.g.
using simple CMOS gates of which there are many in a singe device.)
Fitting the 4060 with appropriate RC elements (see datasheet) one can
make long timers with this IC alone. By AND-ing divider ports short
"on" periods can be made. Or you can trigger a second 4060 device for
more flexible "on" time.
4060 can be used in "one shot" mode by e.g. blocking the oscillator
via a diode connected to an appropriate divider gate. Reset will
restart the whole thing.