Post by thread:[EE] Mercury coulometer

A while back there was discussion of non-volatile displays. I found one that nobody thought of: The Mercury Coulometer An obscure, antique, highly toxic device that has a glass tube, two electrodes, and two columns of mercury separated by a liquid electrolyte. Electrical current passing through the device transfers mercury from one side of the electrolyte bubble to the other, creating a linear indicator - albeit very very slow, fragile, toxic, etc. See the diagram at the end of this paper for a clearer picture: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700023619_1970023619..pdf -- Martin K

On 11 October 2012 00:27, M.L. <spam_OUTmTakeThisOuTlkeng.net> wrote: > A while back there was discussion of non-volatile displays. I found > one that nobody thought of: > The Mercury Coulometer > > An obscure, antique, highly toxic device that has a glass tube, two > electrodes, and two columns of mercury separated by a liquid > electrolyte. > Electrical current passing through the device transfers mercury from > one side of the electrolyte bubble to the other, creating a linear > indicator - albeit very very slow, fragile, toxic, etc. > > See the diagram at the end of this paper for a clearer picture: > http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700023619_1970023619.pdf > I actually own one of those devices! It is packaged in a form similar to a large, glass bodied fuse with wires soldered to both ends. A graduated paper scale sits behind the mercury column to mark time intervals. Until now I've not known the name of the device, let alone how to drive it. Cheers for the info! -- Brendan Gillatt http://www.brendangillatt.co.u

! On 2012-10-11, at 9:47 AM, Brendan Gillatt <.....brendanKILLspam@spam@brendangillatt.co.uk> wrote: {Quote hidden}> On 11 October 2012 00:27, M.L. <mKILLspamlkeng.net> wrote: >> A while back there was discussion of non-volatile displays. I found >> one that nobody thought of: >> The Mercury Coulometer >> >> An obscure, antique, highly toxic device that has a glass tube, two >> electrodes, and two columns of mercury separated by a liquid >> electrolyte. >> Electrical current passing through the device transfers mercury from >> one side of the electrolyte bubble to the other, creating a linear >> indicator - albeit very very slow, fragile, toxic, etc. >> >> See the diagram at the end of this paper for a clearer picture: >> ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700023619_1970023619.pdf >> > > I actually own one of those devices! It is packaged in a form similar > to a large, glass bodied fuse with wires soldered to both ends. A > graduated paper scale sits behind the mercury column to mark time > intervals. Until now I've not known the name of the device, let alone > how to drive it. I've got one as well, in an old (1970's) Tek dual-beam storage oscilloscope! Something like 0-5000 hours. --sp

You can run them backwards. Spehro <.....speffKILLspam.....interlog.com> wrote: {Quote hidden}> >! > >On 2012-10-11, at 9:47 AM, Brendan Gillatt <EraseMEbrendanspam_OUTTakeThisOuTbrendangillatt.co.uk> wrote: > >> On 11 October 2012 00:27, M.L. <mspam_OUTlkeng.net> wrote: >>> A while back there was discussion of non-volatile displays. I found >>> one that nobody thought of: >>> The Mercury Coulometer >>> >>> An obscure, antique, highly toxic device that has a glass tube, two >>> electrodes, and two columns of mercury separated by a liquid >>> electrolyte. >>> Electrical current passing through the device transfers mercury from >>> one side of the electrolyte bubble to the other, creating a linear >>> indicator - albeit very very slow, fragile, toxic, etc. >>> >>> See the diagram at the end of this paper for a clearer picture: >>> ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700023619_1970023619.pdf >>> >> >> I actually own one of those devices! It is packaged in a form similar >> to a large, glass bodied fuse with wires soldered to both ends. A >> graduated paper scale sits behind the mercury column to mark time >> intervals. Until now I've not known the name of the device, let alone >> how to drive it. > >I've got one as well, in an old (1970's) Tek dual-beam storage oscilloscope! >Something like 0-5000 hours. > >--sp > > > >