warning lamp with Euro lights

[mike]

reed switch...glass tube c. 1" long 1/8" dia...has two
contacts inside that can be made to close with a
magnetic field, they are often used in burglar alarms,
(magnet fixed to door, switch fixed to frame)

they will also operate with a few turns of wire
carrying 5A dc. ie the sort of current indicators take

mike


--- Larry C Leung <l.leung at juno.com> wrote: > Hmm,
must be more sensitive devices (or more
> current) than any of the
> isntruments that I have access to in the High School
> lab (never spent
> series time in the EE department in college.
>
> LL - NY
>
> On Sat, 17 Nov 2001 17:30:28 +0000 (GMT)
> =?iso-8859-1?q?mike?=
> <mikemk40 at yahoo.com> writes:
> >nah...i've got one for trailer indicator
> lights....two
> >or three turns closes the reed switch with three
> bulbs
> >(car+trailer), doesn't close it with two bulbs (car
> >alone or car and trailer with blown bulb)
> >
> >Use the switch to signal trailer bulbs working
> (legal
> >requirement in the uk)
> >
> >Mike
> >
> >  --- larry C leung <l.leung at juno.com> wrote: > It
> >would take a heck of a lot of turns...
> >>
> >> the Physics Teacher
> >>
> >> On Tue, 13 Nov 2001 20:59:59 +0000 (GMT)
> >> =?iso-8859-1?q?mike?=
> >> <mikemk40 at yahoo.com> writes:
> >> >Anybody thought about putting a couple of turns
> of
> >> the
> >> >headlight wire round a reed switch and using
> that
> >> as
> >> >an input to the lamp monitor?
> >> >
> >> >mike
> >> >
> >> > --- Phil Payne <quattro at isham-research.com>
> wrote:
> >> >
> >> >> Theory: Current would be measured very simply
> by
> >> a
> >> >> coil around the wire -
> >> >> > the coil wire should have some voltage when
> >> >> current flows through the
> >> >> > headlight wire.
> >> >>
> >> >> Bad theory.  You will only get a current in
> your
> >> >> coil when the current in
> >> >> the wire _changes_.
> >> >>
> >> >> --
> >> >>   Phil Payne
> >> >>   http://www.isham-research.com
> >> >>   +44 7785 302 803
> >> >>   +49 173 6242039
> >> >>
> >> >>
> >> >
> >>
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