# Normally closed glass reed switches

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#### Heywood Jablome

Jan 1, 1970
0
Just looked at RS, Jaycar and Dick Smiths,

I'm looking for a glass reed switch that is normally closed. Can't seem to
find a supplier that has any for a decent price.

I need 50 of them and while most people dont stock them, RS wants over $4 each. Im too tight to pay that much as I can see that Electus has the normally open variety well under a dollar. (but no normally closed ones) Anyone have any other suppliers they care to share? A #### atec77 Jan 1, 1970 0 Heywood said: Just looked at RS, Jaycar and Dick Smiths, I'm looking for a glass reed switch that is normally closed. Can't seem to find a supplier that has any for a decent price. I need 50 of them and while most people dont stock them, RS wants over$4
each. Im too tight to pay that much as I can see that Electus has the
normally open variety well under a dollar. (but no normally closed ones)

Anyone have any other suppliers they care to share?
They come in the elcheapo DS alarm it so they must be available . I
sourced some a while back from direct alarm supplies at a very
reasonable price .

K

#### Kevin Martin

Jan 1, 1970
0
Heywood said:
Just looked at RS, Jaycar and Dick Smiths,

I'm looking for a glass reed switch that is normally closed. Can't seem to
find a supplier that has any for a decent price.

I need 50 of them and while most people dont stock them, RS wants over $4 each. Im too tight to pay that much as I can see that Electus has the normally open variety well under a dollar. (but no normally closed ones) Anyone have any other suppliers they care to share? Well if I look at DSE page and do a search for reed switches. The top of the list is a N/C one for$1.50 (P7856). What's the matter with you? I'm
sure they will do a better price for 50.

Kevin Martin

H

#### Heywood Jablome

Jan 1, 1970
0
Kevin Martin said:
Well if I look at DSE page and do a search for reed switches. The top of
the list is a N/C one for $1.50 (P7856). What's the matter with you? I'm sure they will do a better price for 50. Kevin Martin Thanks Kevin but the search continues. The Dick Smith reed switch is normally closed in the presence of a magnet. To me this means that it is normally open in its normal state (form A). Some may disagree with my terminology. In any case I need one that stays closed when not in the presence of a magnetic field, and opens when a magnet is brought towards it. This is a little harder to find but its not impossible. I purchased a Form C reed today from RS components. At over$6 it was OK for one prototype but not
good enough for quantities of 50 plus. (they only give you a dollar off at
25 units)

So the question remains where I can get a normally closed glass reed switch
at a decent quantity price sub $1. H #### Heywood Jablome Jan 1, 1970 0 atec77 said: They come in the elcheapo DS alarm it so they must be available . I sourced some a while back from direct alarm supplies at a very reasonable price . I think you are talking about the plastic box ones. I'm after the glass reed insert that is inside them. Just the insert, not the casing. I don't think DAS would have them. H #### Heywood Jablome Jan 1, 1970 0 atec77 said: They come in the elcheapo DS alarm it so they must be available . I sourced some a while back from direct alarm supplies at a very reasonable price . I think you are talking about the plastic box ones. I'm after the glass reed insert that is inside them. Just the insert, not the casing. I don't think DAS would have them. S #### sam Jan 1, 1970 0 Heywood said: So the question remains where I can get a normally closed glass reed switch at a decent quantity price sub$1.

If worst came to worst, could your application use a transistor inverter circuit with a normally
open switch?

Cheers,
Sam

A

#### atec77

Jan 1, 1970
0
Heywood said:
I think you are talking about the plastic box ones.
no , ring them and ask
I'm after the glass reed
insert that is inside them.
Just the insert, not the casing.

I don't think
I believe you

H

#### Heywood Jablome

Jan 1, 1970
0
atec77 said:
no , ring them and ask
I'm after the glass reed
Just the insert, not the casing.

I don't think
I believe you

No worries. I'll call them, thanks.

J

#### John Dunkley

Jan 1, 1970
0
It is possible to 'bias' a NO reed switch with a small magnet to make it NC,
and then use your main magnet to bias it off.

I know this works because I have done it.

Just need a supply of small magnets and position it to bias the reed switch
on.

JD

H

#### Heywood Jablome

Jan 1, 1970
0
Jasen Betts said:
Jaycar has them (cat# SM-1002) the 25+ rate is $1.20 AU each, Bye. Jasen Nope. They are normally open. T #### two bob Jan 1, 1970 0 Just looked at RS, Jaycar and Dick Smiths, Jaycar has them (cat# SM-1002) the 25+ rate is$1.20 AU each,

SM1002 is a N/O switch.
It may be easier to find a changeover than a N/C

M

#### Mark Kelepouris

Jan 1, 1970
0
Jasen Betts said:
Jaycar do too.

How about using a reed switch that's open in the absence of a field and
gluing a small ceramic magnet near the reed to close it so that an
opposing magnetic field can cancel its field and open the reed switch.

--

I like your lateral thinking Jasen, it would be interesting to know if that
arrangement would make a reed switch last longer or shorter.

Mark K.

T

#### two bob

Jan 1, 1970
0
Thanks Kevin but the search continues. The Dick Smith reed switch is
I like your lateral thinking Jasen, it would be interesting to know if
that arrangement would make a reed switch last longer or shorter.

Sounds very hit and miss to me, and very unreliable.

A

Jan 1, 1970
0

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