From: "C what I mean" <"NO SPAM"@yahll.com>
Subject: Re: Timer circuit for relay?
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NNTP-Posting-Date: Tue, 01 Oct 2002 16:13:32 GMT
Organization: AT&T Broadband
Date: Tue, 01 Oct 2002 16:13:33 GMT
You can actually do this with one 555 or you can save some trouble and go by
an interval timer from SSAC or IDEC for somewhere between 45 and 65 bucks.
I guess it depends on what your time is worth. Also consider that you have
to not only make the 555 circuit, but you have to have a power supply of
some sort. Then you have to package it and so on. If this is a hobby
thing.. perhaps it would be fun. If it is for a real application.. consider
taking a look at those premade timers.
A good source for 555 info is the "555 Timer Cookbook" if it is still in
print. That particular circuit is in the book if I remember correctly from
so many years ago.
"DaveC" wrote in message
> Posted elsewhere in these groups is my original question, "555 Timer
> Well, I thought that there might be another way to approach this circuit.
> I need to turn on a relay once an hour for a few minutes. The "once an
> needs to be adjustable -- maybe between 45 and 75 minutes, and the "few
> minutes" should be between 5 and 20 minutes.
> How about running a 555 to generate a clock signal as in input to a
> which, once an hour, outputs a signal (ie, goes low). This triggers
> 555 which closes the relay for the shorter period.
> If the clock signal 555 is adjustable -- say, plus and minus 40 percent,
> "once an hour" output from the counter will change accordingly (ie,
> earlier or later).
> The relay-controlling 555 will be simple, adjustable 555 monostable
> Constructive criticism? Ways to improve on this?
> Note that my return address is corrupted in an attempt to reduce spam. If
> choose to e-mail me, please correct my address as described below.
> Dave Carpenter
> Sound Logic
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