Re: Looking for a Low Cost On Delay Timer

["Guv Bob" <guvbob2003@xxxxxxxxxxxxxxxxxxxxxx>]

"John Sowden" <jsowden@xxxxxxxxxxxxxxxxxx> wrote in message =
news:l242ch$4tb$1@xxxxxxxxxxxxxxxx
> On 08/21/2013 10:39 AM, Guv Bob wrote:
> > Names can be confusing, so here's what I'm doing....
> >
> > http://img43.imageshack.us/img43/7434/wvm.gif
> >
> > When 12VDC is applied to the input, I need a 12VDC output for 5 =
seconds.  Then output will go back off and stay off until the input goes =
to zero.  Then cycle starts again.
> >
> > Current for both legs is in the 10-50ma range.
> >
> > A simple on-delay timer would work but I'm having trouble finding =
one with NC contacts.  Tons of stuff $100+, but for this application, it =
has to be under $20.
> >
> > Thanks,
> >
> >
> > Bob
> >
> Get a sensitive relay (coil 1k ohms or so), put about a 3ooo uf=20
> capacitor across the coil, apply 12 volts to the coil, the relay will=20
> hold closed while the cap is discharging into the coil.  Use the n/o=20
> contacts to do what you want.
>=20
>=20
> John Sowden
> American Sentry Systems, Inc.
> San Francisco Bay Area

Thanks John.