cheechQ,
Thanks for giving us a little more details to go on, water is not the best electrolyte, although with enough impurity's it will conduct electricity and will dissolve some metal ions in solution, the water itself can be split into H and OH creating more of an environment for becoming an electrolyte as Hydrogen or oxygen escape the solution could become somewhat caustic holding the metal cation ions in solution easier in with the hydroxide anions in solution.
What you are trying to do will not work that well, both metals will be forced to dissolve at the anode by the force of electrolysis from the power supply pulling electrons from the anode metal atoms t=freeing the metal as ions in solution in the electrolyte, these metal cations will migrate to the cathode area where they are reduced gaining electrons at the cathode and plating out of solution as metal atoms, basically you will not separate the copper silver and other metals. the anode will oxidize all of the metals in the spoon and they will reduce at the cathode.
It will work to break down the metals from a solid bar to more of a metal powder but not separate them.
There is no easy or proven method to do what you are trying to do, there have been several thoughts on trying to find a good electrolyte, or a good method, but none proven to be a good solution to the problem, the problem of separation of metals and an effective way to recover the silver, I have tried several electrolytes with some fair results at making a mixed metal sludge that could be further processed to recover the silver from, but nothing I would call a good method yet.
To be effective a better electrolyte may work, like a concentrated sulfuric acid cell where the base metal copper would not be as apt to dissolve into solution, a 98% H2SO4 acid with a very small amount of HNO3 (5% of electrolyte) may work, I have read where they used this to refinish silver plating to remove silver from the plated articles, (GSP has also commented on this deplating method several times), when they used this method to remove the silver plate they did not recover the silver as they were only interested in removing the silver to re-plate the item, I never tried it but I believe it may work as a method in recovery of silver from the de-plated item, my belief is if run long enough I believe much of the silver should fall out as cathode mud or plate out of solution, although the electrolyte would most likely hold a lot of silver sulfate in the concentrated solution, which if solution was diluted (by pouring concentrated H2SO4 silver sulfate solution into water for safety reasons) the silver sulfate would be less soluble, and then the remaining silver, could be removed from solution as chlorides by adding NaCl to form insoluble silver chloride.
my plan is to someday experiment with it, but as for now I can only guess if it would work or not.
bmgold2,
What you are looking for is a 555 timer circuit with a 50% duty cycle pulse width modulated circuit, you can search for schematics on this circuit until you find one you like, here are a couple of tutorials that can help get you started, the 555 timer IC (integrated circuit) is a great circuit you can build a lot of different things by changing a few external components, it is a very use circuit to learn, you can build hundreds of very useful things from this little chip.
You can find tons of information and circuits using the 555 timers IC.
Here are a couple of tutorials which can help you learn to build a modulated 50% duty cycle power supply.
http://www.williamson-labs.com/555-circuits.htm#50
http://www.electronics.dit.ie/staff/mtully/555 folder/555 timer.htm
