Hi Bob, Am I missing something here? I thought voltage had nothing to with making CS other than allowing current flow through the water. I thought it was current density that was most important and the voltage could start at any potential as long as it didn't allow too much current flow for the surface area. That's the reasoning behind constant current control.
Our SG7 Pro starts at 75 volts but reduces the voltage as necessary to maintain a constant current of about 2 ma/square inch. I'm almost positive no nitric acid is formed but am willing to be convinced. Can you explain how constant current density in that range will do that? I have made DC generators with as much as 325 volts at startup but with current limiting to keep current density at or below 2 ma/square inch of anode and it always produces CS which is the same as that which is made with considerably less voltage....current density staying the same of course. The only difference I ever noticed was the amount of time it takes to get up to the preset current limit. Higher voltages just get you started more quickly. I can't see that voltage has any bearing on producing nitric acid UNLESS one is using an arcing method. Is that what you're talking about? Or are you talking about using constant voltage setups where the current can rise beyond the established current density limits? Is it the higher current flows that make for nitric acid? Trem Greetings Ya'all, Not ALL CS is benign!. Beware of those who tinker with high voltage AC or DC as they do generate NO3 and NO. The legal limit of NO3 is 10 ppm and on NO is 1 ppm. Let's just place high voltage at over 50 volts. I have measured NO3 at 1 PPM in 37v CS. One can measure NO3 which forms nitric acid in the CS with over the counter chemicals, but NO can only be measured with a spectrophotometer. On experimenter when warned checked the NO3 in his HVAC ARC CS at 100 PPM. That is BAD news, besides being ten times the legal limit. At above 10 ppm it will etch your teeth. Been there done that! As reported earlier 1.2 volts does make good CS. It takes a bit longer, but there is no silver oxide or silver peroxide formed, which translates into the fact that you never have to clean electrodes. "Ole Bob"
