-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Mon, May 14, 2007 at 10:50:07PM +0000, Peter P. wrote: > Vitaliy maksimov.org> writes: > > > I'm intrigued. So, how is the thing actually used? Once the bubble gets to > > one side, the current stops? > > No, the electrode is 'eaten' and that is not reversible because usually a gas > bubble forms and cuts the current. But normally technicians invert the device in > its socket when it is near the end marker and then you have another 1000 hours > to go. This can be repeated a number of times before the device fails. The > device can be killed by passing too much current. If a gas bubble develops (and > it will) then it's dead. The bubble can be seen against a strong light (the > 'salt' solution is black or yellowish-dark, the bubble is clear and usually > elsewhere than where the salt solution is). Also afaik the 'slat' is HgCl2 . Not > very healthy but a tiny amount. I could be wrong on this though. Interesting... Mercury chloride is probably not too hard to obtain, although as you say it is very toxic stuff. The mercury again is easy to get, especially in the tiny quantities needed. Be an interesting experiment to try to make one of these myself. Probably won't be accurate, but it will work. Mind you... would it have been Hg2Cl2 instead? According to wikipedia that is used as a reference electrode for it's stability and accuracy. Decomposes upon exposure to UV light, but then again they are encased in glass which IIRC filters UV light. - -- http://petertodd.ca -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGSQjM3bMhDbI9xWQRAg3AAKCY9bzurgUBp0TRA1ed8xMeafgkcACgnwxW ANs8MGR7hYOmfgIPxedmSSQ= =A78h -----END PGP SIGNATURE----- -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist