A colloidal silver generator
I designed and built 10 years ago. It's interesting going back ten years to see what your designs were like, and to see if you can still figure out how it all works!
U2D allows for a pseudo-split supply by providing VBias.
U1A is a long timer set to about 60 seconds if I recall correctly, and U1B is configured as an inverter. The silver wire probes are connected to points P1 and P2 which alternate polarity between +15V and -15V so that silver migrates off each probe equally. R5 limits the maximum current in the colloidal solution to about 135mA, which should never be reached in practice.
R5 also acts as a current sensing resistor, and the voltage across it is sampled by the differential amplifier of U2A. This voltage is fed to U2B which is a positive peak detector having a decay time of about 2 seconds. As the silver concentration increases, the peak detector output voltage increases until it reaches the voltage threshold placed on U2C and set by RV1. When the threshold is exceeded, comparator U2C toggles and clocks in the HI D-bit to the Q outputs, one which sets the "Process Complete" LED, and the other turns off the switch Q3 which feeds V+ to U1A and U1B, causing the electrolysis process to cease.
With the proper water (starting resistance between 25k and 100k between two 1-inch silver wires separated by about 2 inches), the process takes about 4 hours to complete, and it is fully automated. Set it up and leave it. The next batch is not possible until the power to the device is cycled to reset the D-flip-flop.
This unit is a constant voltage device, which causes an exponential rate of electrolysis, so some experimenting is required for setting the "Concentration" potentiometer. A better design is one where the output is constant current, say 1mA or so. The constant current design was in the works 10 years ago, but not quite finished. A day or two design work would allow completion of that version. This one however is a good start for anyone that wants a cheap half-smart colloidal silver generator.
PS. Be sure to view the schematic using "Windows Picture and Fax Viewer" (which re-sizes it properly) or something equivalent that properly re-sizes the graphic without butchering the quality as this viewer does
« Last Edit: 2010-01-19, 03:42:25 by poynt99 »