Hi Trem, Thanks. I stand by what I said. Current density is found by the expression: I(Amps) / A(mm2) = Amps per square millimetre. One can lessen the current density by either increasing the electrode area or decreasing the current, both have the same result. Which method one chooses has to do with the relationship one desires in total current vs resistance vs voltage. As for current density vs particle size... I believe silver is stripped from the anode and enters the water as single ions no matter what the current, whatever causes aggregation occurs after this.
Ivan > Hello Ivan, > > Well said. I guess the only thing I might disagree with is the electrode > surface area not being a function of particle size. My feeling is that if > the current density is high, the particle size increases because the ions > are being more forcibly ripped off the electrode. It rings true with me and > is borne out in my experiments that more surface area makes better CS if the > current is held low. That's why I originally chose to use flat electrodes > in order to get more surface area. The current density theory mentioned by > Bob Lee about starved electrodes makes it ring more true. > > I hope we're getting to the end of this discussion. It's like the blind > guys trying to describe the elephant without being able to see the whole > thing. > > Trem > > ----- Original Message ----- > From: Ivan Anderson <[email protected]> > To: <[email protected]> > Sent: Friday, August 06, 1999 4:11 AM > Subject: CS>Generators, Current regulation, etc > > > > > > I notice the discussion of current regulation, electrode geometry > > etc. > > Here is my 2 cents worth. > > Every one is correct in this discussion as far as they go. > > All generators work in exactly the same manner, that is sintering > > silver atoms from the anode (positive electrode), and all produce > > perfectly good CS within certain boundaries and limits. > > > > The difference in generators is really in the ease of use and the > > concentration they are able to produce. > > > > The simple 3 or 4 battery method has the advantage of short > > generation time, but requires constant attention (stirring, > > electrode wiping etc.). these generators produce fine CS in the 5 > > to 10 ppm range. The conductivity of the water past this range > > allows too high a current flow, and that coupled with a quite > > high voltage causes a high particle mobility. The consequence of > > this is that many particles contact the cathode (negative > > electrode) and are reduced to the residue or treeing we see. This > > residue enevitably finds its way into the solution which results > > in the cloudy, dark and unstable colloid we see many questions > > about. > > Hot water limits these factors to some extent, mainly by the > > convection currents in the water mixing the silver plume through > > out the solution. > > > > Constant current (current limiting) generators over come many of > > the problems described above by limiting the current to a value, > > where the number of particles coming off the anode is not so > > great that they cannot be spread throughout the solution before > > they meet the cathode. As the resistance in the solution falls > > (with the introduction of silver particles) in this type of > > generator, the voltage drops and therefore so does the particle > > mobility. This is a most beneficial set of circumstances. The > > more particles there are in the water, the less energy they have > > in movement, and the less likely they are to be reduced at the > > cathode and the less energy do they have to overcome > > electrostatic repulsion when they encounter each other. As long > > as the voltage stays above about 1V the generator will continue > > to disassociate silver ions from the anode. > > These generators can produce clear or light yellow colloid to > > high concentration (10 ppm +), but are more technical and > > expensive to implement, and require more time to generate a given > > concentration. > > > > The pulsed generators and polarity switching generators can be > > thought of as current limiting hybrids and seem to exhibit many > > of their positives and negatives. > > > > Low voltage generators (9 to 15volt) are very simple to implement > > and also display the positives of current limit devices, due to > > the slow manner in which they dissasociate the anode into the > > water, but above a certain point they behave like the higher > > voltage units. Good up to about 15ppm. Long generating time. > > > > Electrode configuration and crossection affect CS generation only > > in as much as they have an influence on the maximum current draw, > > and the distance the silver ions have to travel before they meet > > the cathode. An arrangement that is constant in geometry will > > have reproducable results. > > > > Particle size is a much discussed and overly emphasised part of > > CS generation. Particle size, as determined by colour, is > > effective from clear through yellow-green, yellow and gold. The > > range is apparently <1nm to 15nm (<.001micron to .015micron) > > and, as you can see, the difference is slight. All exhibit very > > good stability and antimicrobial proterties. > > > > Ivan > > > > > > > > > > > > > > -- > > The silver-list is a moderated forum for discussion of colloidal silver. > > > > To join or quit silver-list or silver-digest send an e-mail message to: > > [email protected] -or- [email protected] > > with the word subscribe or unsubscribe in the SUBJECT line. > > > > To post, address your message to: [email protected] > > > > List maintainer: Mike Devour <[email protected]> > > > > > > > > > -- > The silver-list is a moderated forum for discussion of colloidal silver. > > To join or quit silver-list or silver-digest send an e-mail message to: > [email protected] -or- [email protected] > with the word subscribe or unsubscribe in the SUBJECT line. > > To post, address your message to: [email protected] > > List maintainer: Mike Devour <[email protected]> > -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
