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Normally closed glass reed switches

H

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.
ring them and ask
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
ring them and ask
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.
 
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