Hello again.
I built a vertical "bug" style CW key (W.R. Smith designed) and it works fine, or did, but during a recent move the dot magnetic reed switch was broken. Major bummer as I had it dialed in pretty well. It was making well over 100 dots in a row. I was using a double pole miniature magnetic reed switch and closing the normally open contact. I had another of the same type of reed switch that I installed but the issue was that once made, the connection wouldn't break unless I moved the reed far away from the magnet. Obviously this wasn't going to work for CW so I order a bunch of single pole, "little Fuse" brand subminiature switches thinking that if I had to try a couple to find one that was faster on break than the others I would have them.
The first switch I tested seemed to work great until I took a phone call and I guess while it was loose in the mounting tube it must have been in the magnetic field too long as it started doing the same thing. Once a dot was made, it wouldn't break. The make break pendulum distance is only about maybe 1/32nd inch when working, maybe even less. So for the heck of it, I reversed the switch and now it works fine. This doesn't make sense since if the switch became magnetized, if that was the issue, it shouldn't matter from what side it gets closed to then break.
So is a constant magnetic field causing the switch to get magnetized so that once made it doesn't break? I can see where the pull-in would need to be greater than the holding magnetism, but when I had the switch reversed, I had to move it about an inch away from the magnet in order to get it to break. Whereas when it works correctly, it makes and breaks within 1/32 or less.
Anyone have experience with these small magnetic reed switches?
Thanks!
Jerry