Understanding Reed Switches & Reed Relays

[@Ezzell_]

Does the orientation of the reeds and or the the magnetic field come into play?

[@ElectronicsNotes]

Not that I am aware of. They seem to demagnetise well after the field is removed , so it does not appear to be an issue.

[@Big74Mike2012]

I have Reed switches all around my house at this point (cabinet & closet lighting, intruder alerts on windows, etc), and I've tried just about everything I can think of (or Google), but I have yet to find a way to get the contacts inside the reed switches to stop fusing together after a couple of weeks to a couple of months! Even using as little as 5v 60mA, they always seem to go bad pretty quickly. Any ideas would be appreciated....

[@ElectronicsNotes]

That is very annoying. I didn’t have trouble with that when I used one. I wonder if you are switching an inductive load. The sparks from the back emf can kill reed switches very quickly. Also if you are driving a capacitive load, the inrush current when the reed is switched over can fuse them. I suggest having a look at these aspects and also trying some higher rated reeds. I hope this helps.

[@flixi007]

thank you for the video, its very helpful

[@ElectronicsNotes]

I’m really glad you found the video useful. Thanks for your comment.

[@ricksampson6780]

Can you please discuss the various methods of recovering the BEMF generated when a relay coil is de-energised. Recovery values of 80-90% of the input power in a pulsed relay driver circuit are possible, given the correct circuit/coil parameters. Cheers.

[@ElectronicsNotes]

This is not something I have done, but I am sure there is someone out there who has done it. When I’ve used them I have not been in a situation where I needed to recover the back EMF.

[@ricksampson6780]

@@ElectronicsNotesI have working examples in my Lab if your interested in further discussion/schematics.

[@ElectronicsNotes]

@@ricksampson6780 that would be interesting. Thanks.

[@princessannora8219]

☀️ 'promo sm'