Can anyone point me towards a UK source (phone or online) for an inexpensive cylindrical, enclosed reed switch, N/C, for use in a burglar alarm circuit please.
I'm still googling but so far without success and want to place an order for delivery Monday.
"electronic-parts distributor" in the UK implies a trade only source with limited interest in selling to retail customers. Those that do, typically charge exorbitant delivery, minimun order and service charges
- leaving the only real alternative to be a toy shop called Maplin. Or eBay.
There is no such thing as a NC reed switch. The induced magnetism in the reeds *always* attracts them together when you bring the magnet up, and never repels them so all two terminal bare reed switches are NO. It is possible to put an additional non-magnetic reed in the capsule, so that one of the magnetic reeds is in contact with it until an external magnetic field is applied, but as the reeds have to be brought out through the pinch of the glass capsule to support them, this provides a SPDT switch, not a NC one although it can be used as such.
If he googles 'SPDT reed switch' (without the quotes), both Rapid and Maplin stock them. but for alarm use, I'm fairly sure he wants a complete reed sensor and magnet pair for a NC loop, NOT a bare reed capsule.
If he's looking for a switch/magnet pair he can mount in the edge of a door and its frame in drilled holes, googling 'recessed reed switch' will find plenty, all NC in the presence of their magnet (i.e. with the door closed). Again Maplin have some.
If he wants a true NC action, he's either going to have to stick a bare SPDT reed in a cylindrical housing e.g a plastic tube from a biro with a dab of hot glue or mess around with a biasing magnet to cancel out the field of the actuating magnet as it approaches. Enclosed SPDT reed switches, although nearly as rare as hens teeth, are available but apparently not in a cylindrical recessed format.
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Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
No Radio Shack there? Try an alarm company then... They were commonly used in the big dish satellite systems on the positioning motor, but since big dishes are uncommon now, that's not a good source, but some satellite dish companies may have a few sitting on the shelf.
You can deal as an individual but on small quantities you pay postage, don't get free technical support etc.. Basically 2nd class treatment and they make you feel that. Attempts at getting trade registration for my credit worthy limited company failed at Farnell without an explanation why :-(
It takes a bit longer, but I find eBay works for me. If it's urgent, then Maplin, Cricklewood Electronics or me turning up at an RS trade counter with my VAT registration certificate (yes really).
BTW Radio Shack pulled out years ago. Now that was a toy shop...
I've never had a problem with CPC that wasn't resolved with an e-mail or two. According to
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it's 'Small Order Handling Charges', not postage, that they levy on orders smaller than £45 ex VAT. I guess this amounts to the same, but I don't think I've ever needed to trouble them with less than 45 quids' worth.
Find one where you can walk in off the street during business hours if you demonstrate posession of atleast half a clue when you walk in and pay cash they'll treat you ok.
The only one in the UK which has trade counters in several cities is RS Components - and they won't serve someone walking in off the street. And rightly so - a genuine client shouldn't have to wait while an amateur asks for advice, etc.
Maplin is the place for that sort of thing.
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*I can see your point, but I still think you\'re full of shit.
Dave Plowman dave@davenoise.co.uk London SW
I buy from CPC weekly, my orders generally are for more than the minumum carriage free amount, £45 IIRC, but I think it`s only a few pounds for standard delivery.
As far as CPC being trade only. that`s a laugh, it was a big bone of contention a few years ago when they started putting their weekly special offer leaflets in punter magazines and opened a 'trade counter' that is open to all. I`ve dealt with CPC since the early 80`s, they are a good company, I`ve had very few problems, and complains are dealt with asap.
Farnell also will hapily sell to the public via their website - The Farnell organisation own CPC btw, I`ve also had good dealings with Rapid Online.
The word is grudgingly. Both CPC and Farnell technical support is free for account holders, and there is no minimum order for trade customers. Other companies even have free post for trade customers on any order size. Because on things like internet sales they have to agree to "distance selling regulations" and similar, they end up losing money dealing with consumers. Maplin is the only UK national choice for hobbyists and small time repairers like me.
Never mind, if it works for you. Good :-)
eBay and purchasing outside the UK works for me and yes; I know what a scam fest eBay can sometimes be, but not in this case.
For example I recently had to replace a shot schottky SMD diode in a HP printer SMPS. Per part, 20p each from Farnell. Minimun order charge £20. Post and packing £4.25.
From an eBay seller in the states, £8 including postage for 500 diodes. They were delivered within the week.
If it's urgent I jump in the car and find something in a shop closer. Or risk a dodgy substitute for the part, which I really shouldn't do if it's critical ....
Yeah they are happy to take your money whoever you are, the days of the 'trade only' wholesalers is more or less over. You fill in the order form, authorise the credit card and the goods arrive next day, what`s so dificult to understand about that?
That`s because Farnell are in business to make money not cater for hobbyists who want one diode. Do you want them to lose money so that you can fix your printer on the cheap?
If you don't like CPC or Farnell, I suggest you try Rapid Electronics.
Well, you are lucky to have a shop nearby which sells electronic components. They are sadly few and far between these days.
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