Article: 14509 of alt.horology From: "Revision" Newsgroups: alt.horology Subject: Re: whats the most accurate (non radio,digital display) watch? Date: Tue, 29 Jun 2004 01:39:49 -0500 Organization: Posted via Supernews, http://www.supernews.com Message-ID: <10e23ln3382kd4e@corp.supernews.com> Reply-To: "Revision" References: <2jpt3pF13ppvfU1@uni-berlin.de> <10dfilclgj5d969@corp.supernews.com> X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Complaints-To: abuse@supernews.com Lines: 22 Path: news.meer.net!newsread1.mlpsca01.us.to.verio.net!newsartnum1.dllstx09.us.to.verio.net!newspeer1.dllstx09.us.to.verio.net!news.verio.net!border1.nntp.sjc.giganews.com!nntp.giganews.com!sjc1.usenetserver.com!news.usenetserver.com!news.tele.dk!news.tele.dk!small.news.tele.dk!sn-xit-02!sn-xit-01!sn-post-01!supernews.com!corp.supernews.com!not-for-mail Xref: archive.mv.meer.net alt.horology:14509 "Jack Denver" > http://www.semiconductors.philips.com/acrobat/datasheets/PCA2002_3.pdf I enjoyed reading how the programming of the One Time Programmable memory is accomplished using the power supply pins. The OTP memory is basically just a field effect transistor with a floating gate sandwiched in the middle. Since there is no way to discharge this floating gate once it is charged, it is "one time programmable." The charge lasts for ten years, which works out to the loss of one electron per week. http://www.semiconductors.philips.com/news/content/file_181.html This (PCA2002 data sheet) finally explains how they trim modern quartz watches. Many thanks.