Some attributes of any mechanism are global. Beyond the capacity to do a job, size, weight, number of
connection wires, time and procedures to set up and operate are elements to be minimized.
Some attributes of any mechanism are global. Beyond the capacity to do a job, size, weight, number of
connection wires, time and procedures to set up and operate are elements to be minimized.
Additionally, for a nano silver generator, these considerations come to mind:
Our evaluation unit is currently housed in a 2.25 x 3.6 x 1.0" prototyping box. It incorporates these design elements in the following ways:
Power universality: we have chosen a 5VDC cell phone charger as the power source. Alternatively, a USB cable is being considered since it is widely available, has 5VDC on it and has a polarized connector.
Output polarity reversing: Claims have been made that reversing the polarity periodically keeps electrodes clean so they do not have to be buffed with a scrubbie between runs, so we have incorporated this. However, the optimum switching time period has not yet been determined.
Constant current: We are presently in agreement with others that constant and smaller current produces a better preparation. The appropriate quantity has not yet been determined. Our unit incorporates a DC-DC converter that puts out up to 80V to drive 0.6mA through the bath. This high voltage enables the process to start up quickly.
Stirring motor drive: We are
currently agnostic regarding the need to stir the bath, which some others claim as essential.
However, we have incorporated a current-limited stirring motor drive that drives a small DC motor
with a 4 seconds on/4 seconds off duty cycle for the duration of the preparation time. A red LED
glows brightly if current limit is exceeded. Stirring seems preferable to bubbling air through
the bath since air can introduce dust and oxygen, which may not be desirable. In any event, our
stirrer stirs the sauce perhaps too vigorously. More work is needed.
Visible evidence of current flow and polarity: A high-efficiency LED, which glows brightly with 1 mA of current, is used to indicate each polarity of current through the preparation. Since the same current flowing through each of the LEDs also flows through the bath, if an LED is not on, we know we are not making Nano Ag. When both LEDs are out, the unit has shut down.
Automatic shutoff: shutoff at ~17 kilohms of bath resistance or 5 hours, whichever comes first. The unit also shuts down if the electrode outputs are shorted. Removing the power, waiting a second or two, and re-applying power starts the unit back up. With auto shutoff based on conductivity of the preparation, the generation can be interrupted at any time, then resumed later.
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