Square Wave Voltammetry

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Aswinpk94
Level 2
Level 2
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I am performing Square wave voltammetry using PSoC 5LP. In it, a square wave is superimposed on a base staircase potential. It is then applied to an electrochemical cell with a 3 electrode configuration. I have generated a waveform. Now I want to test it before applying it to the cell. I need to perform both DC and AC analysis of the circuit. Does anybody have any suggestions?

Experiment conditions: Potential range: -1 to +1V. Width of pulse: 25ms. Max current to be sourced at the cell: 100 microAmps(0.1mA).

Perform AC analysis on different time constants and measure current

 Steady state DC AnalysisSteady state DC AnalysisTest circuitTest circuitAC analysis schematicAC analysis schematicSquare+staircaseSquare+staircaseand share your views on the schematic I shared with this?

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Vasanth
Moderator
Moderator
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250 sign-ins 500 solutions authored First question asked

Hi Ashwin,

The same ADC is being used and we are changing the inputs to the ADC. 

 

Vasanth_0-1633943080978.png

The AMux is in differential configuration with 2 channels and Amux_Select() API can be used to connect the channel(check component datasheet).

Best Regards,
Vasanth

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Vasanth
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250 sign-ins 500 solutions authored First question asked

Hi,

Some suggestions, you can use one more another ADC channel to measure the voltage across the test circuit. To connect multiple inputs you can use a AMux component and switch between channels. The V and I measured in this way can be transferred to your PC using USB-UART or some other interface. You can manually change the test circuit resistances and cap values and in the test circuit to check the time constant.

Best Regards,
Vasanth

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Thanking you first for your valuable suggestions. I need to apply the potential to an actual electrochemical cell. Before that step, I had decided to test on a basic Randell circuit, which is equivalent to an actual cell.

I have neglected Warburg impedance and chose a Resistor in series to a parallel RC branch and measure current up to 100micro Amps. 

Could you explain the additional ADC channel and use of ADC MuX? Where should be the second ADC to be connected and how can I get accurate data by reducing noise?

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Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi Ashwin,

The same ADC is being used and we are changing the inputs to the ADC. 

 

Vasanth_0-1633943080978.png

The AMux is in differential configuration with 2 channels and Amux_Select() API can be used to connect the channel(check component datasheet).

Best Regards,
Vasanth

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