|Re: LEDs under panel|
Message #9 Posted by J Tiers on 26 Aug 2002, 9:03 a.m.,
in response to message #8 by Ellis Easley
Yeah, likely so, since I have never had an ESD failure or odd operation on any HP or other calculator, for that matter.
However, don't forget that many of the same considerations that come up with a handheld anyway also help ESD immunity. For one, the tough case implies thickness, and hence spacings. Also, dust sealing implies a relatively closed case which tesnds to reduce potential paths.
Finally, the usual type of clamshell case is generally accomplished with a tongue and groove closure, which lengthens the leakage or arc path.
We make all our equipment in export as well as domestic versions, and the basic design has to meet FCC/CE/C-tick, etc. I do EMC design evaluations and remediation as well as my regular design work. Part of that is ESD, although that tends to be inherent after the other items are satisfied. So I have some familiarity with the issues, and you are correct. I agree that if ANY company was interested in ESD back then, HP would have been it.
Now that they want to make nothing, I suspect they are less fussy.