Reed switches chirping

[Ice-Tea]

Hello folks,

I have had two pieces of gear, vastly different ones, "chirp" on me recently. Both times, I think, it were Reed switches. I've been browing around a bit and can't seem to find much info on this. What are your experiences? And is this "yeah, that's just the way Reed relays roll" or is this "That one is almost gone"? As far as I can tell, no functionality is impacted...

Thoughts?

[WattsThat]

I dunno. Could just be what it does?

I’ve worked with several reed relay based devices over the years, kind of got used to the call of the crickets. The best was a Julie Research Labs digital meter, circa 1975, were the kelvin varley divider was automated with reed relays. When you made a measurement and the bridge would null, the reed relays sounded like the hottest summer night you’ve ever heard. It was nice because you never looked at the Numitron display until the crickets were quiet. Only then was the measurement stable.

[Ice-Tea]

The odd thing is there is so little info to be found about it? It seems to be in the DNA of some people "in the know", but I can't seem to find anything concrete. Like app notes, mentions in the datasheet or what not.

And I could live with it during warmup, but it raises an eyebrow or two when it does it during normal operation..

[jmelson]

I got a tour of a Bell System #3 ESS many years ago.  All the switching was done with "ferreeds", kind of a combination of magnetic core memory and reed switches, so the ferrites  stored the field that latched the reed contacts.  It had tens of thousands of them.  It made a marvelous sound with all those contacts opening and closing rapidly.  When the contacts close, there is a slight vibration when the energy of the moving armature is transferred to the contact.  And, when the contacts open, there is a different frequency as the armature pulls away and then vibrates like half a tuning fork.  At least, that's what I think causes the sounds.

Jon