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timer circuit
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Jim Yanik
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timer circuit
wrote in :
On Fri, 13 Apr 2012 17:30:22 -0700, Pilgrim
wrote:
Need a ckt. that will give me 2to5 sec. pulse every 1to2 minutes. Would
prefer not to get involved with a microP.
Thanks.
CP
If accuracy isn't critical ( 10% variation either way is OK), then a
pair of 555 timers (or a 556 dual timer) could provide what you
specified.
If timing accuracy is critical, then a simple micro like the PICAXE
(under $5, programmed in BASIC) would be a better choice. For even
better accuracy, you can add a crystal as the clock source and have
one or two seconds per day timekeeping accuracy.
for such long timing periods,use a CMOS 7555/7556.
a neat site I found;
http://www.daycounter.com/Calculator...lculator.phtml
calculates values for 555 astable timers.
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Jim Yanik
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