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Home > Archive > Electronics repair > April 2005 > timer question
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| scott canale 2005-04-16, 3:16 pm |
| o.k., so now i have a timer that will let me adjust between 1 minute and 23
hours and 59 minutes. but now...
when the timer turns off, i need to ring an alarm, a loud and annoying
alarm such as an old fire drill alarm or to signal an alarm that can be tied
into the intercom system at the business. any ideas?????
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| Dave Plowman (News) 2005-04-16, 3:16 pm |
| In article <oVD5e.16652$ZB6.14410@newssvr19.news.prodigy.com>,
scott canale <scanale@prodigy.net> wrote:
quote:
> o.k., so now i have a timer that will let me adjust between 1 minute and
> 23 hours and 59 minutes. but now... when the timer turns off, i need to
> ring an alarm, a loud and annoying alarm such as an old fire drill
> alarm or to signal an alarm that can be tied into the intercom system
> at the business. any ideas?????
The simple way is to use a relay with change over contacts. Feed the coil
off the timeswitch, and when it switches off it makes a connection between
the common and normally closed contacts on the relay.
--
*Your kid may be an honours student, but you're still an idiot.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
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"scott canale" <scanale@prodigy.net> wrote in message
news:oVD5e.16652$ZB6.14410@newssvr19.news.prodigy.com...
quote:
> o.k., so now i have a timer that will let me adjust between 1 minute and
23
quote:
> hours and 59 minutes. but now...
> when the timer turns off, i need to ring an alarm, a loud and annoying
> alarm such as an old fire drill alarm or to signal an alarm that can be
tied
quote:
> into the intercom system at the business. any ideas?????
Connect it to the NC contacts.
--
N
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| Comteck 2005-04-16, 3:16 pm |
| "scott canale" <scanale@prodigy.net> wrote in
news:oVD5e.16652$ZB6.14410@newssvr19.news.prodigy.com:
quote:
> o.k., so now i have a timer that will let me adjust between 1 minute
> and 23 hours and 59 minutes. but now...
> when the timer turns off, i need to ring an alarm, a loud and
> annoying
> alarm such as an old fire drill alarm or to signal an alarm that can
> be tied into the intercom system at the business. any ideas?????
>
>
Your timer should have 2 sets of contacts; N.O. (Normally Open), and N.C.
(Normally Closed). Those contacts simply act as a switch. Connect to the
N.O. contacts, so that when the timer changes state it will close, thus
turning on whichever circuit you may be connected to.
Travis
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"Comteck" <comteck@telus.net> wrote in message
news:Xns9635E83095E5Dcomtecktelusnet@198.161.157.145...
quote:
> "scott canale" <scanale@prodigy.net> wrote in
> news:oVD5e.16652$ZB6.14410@newssvr19.news.prodigy.com:
>
>
> Your timer should have 2 sets of contacts; N.O. (Normally Open), and N.C.
> (Normally Closed). Those contacts simply act as a switch. Connect to the
> N.O. contacts, so that when the timer changes state it will close, thus
> turning on whichever circuit you may be connected to.
You mean NC. NC are closed after the timer runs out.
--
N
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