Data Collected
The first data we collected was our step size for the voltage output from our Arduino Due. To achieve the voltage range of -3 to 3V over the cell we needed to output 2V and 8V from the Arduino. After calculating which Arduino values output 2V and 8V we were able to calculate a theoretical voltage step size of 2.17mV. This range with this step size is represented in the graph below:
In our testing, we found that our output voltages did not scale linearly as we would have expected. Instead, the voltages grew at different rates in different ranges.
Low Voltage:
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Rate: 2mV/step
Medium Voltage:
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Rate: 0.67mV/step
High Voltage:
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Rate: 0.58mV/step
The next data that we collected is the voltage sent out from our summing amplifier (you can see which part of the circuit it's in below) that is being sent to our high current amplifier and then over the electrochemical cell. This voltage is measured with a multi-meter, and determines the range of our potentiostat.
Lower Value:
Expected Value: -3V
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Experimental Value: -3.02V
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Error: .66%
High Value:
Expected Value: 3V
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Experimental Value: 2.88V
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Error: 4%
