Normally closed glass reed switches

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 .

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

So the question remains where I can get a normally closed glass reed switch at a decent quantity price sub $1.

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.

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.

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

Cheers, Sam

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.

Jaycar has them (cat# SM-1002) the 25+ rate is $1.20 AU each,

Bye. Jasen

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

Nope. They are normally open.

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.

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

LA5070 8+ $4.95 LA5074 8+ $5.75 LA5075 8+ $4.75 at

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.

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

NESS Security sell them dont know the cost

REED SWITCH GLASS ONLY N.C. Contacts Part No. SWI540 N.O. Contacts Part No. SWI550