Circuit Design
The Above Circuit Diagram may be Confusing, so Let's Break it Down.
Our Circuit is Composed of the 7 Following Sections:
Power Supply
Our Power Supply is a 12 Volt Direct Current power supply that converts that power you get from a wall socket to use with our design. The main purpose of this power supply is to give power to the microcontroller and buck convertor.
Buck Convertor
Since the Microcontroller can not output the voltages we need directly, the Buck Converter uses a MOSFET to take the voltage directly from our Power Supply and reduce the voltage to a usable level.
Control Amplifier
The Control Amplifier is the feedback loop that ensures stable conditions for the Electrochemical Cell. Using an operation-amplifier we are able to compare the voltage of our signal from the microcontroller and the voltage over the cell, and change the voltages accordingly to self correct.
Microcontroller
The Microcontroller is the "Brain" of the design, and computes and sends out the voltages and currents over the cell. It also then receives and stores the recorded values over the cell. We use an Arduino Due with our design, and this is how the user interfaces to set their scope and receive their final data.
Signal Conditioning
Composed of a unity gain amplifier, summing amplifier, and current booster, the Signal Conditioning circuit refines the signal from the Buck Convertor to be used in the rest of the circuit.
Electrochemical Cell
The Electrochemical Cell is what we are testing with our Potentiostat. The cell receives a current from the previous sections of our circuit, impart some resistance, then output a current. It is this output current that we are interested in measuring.
Voltage/Current Meter
We measure our final values by using an "I/E Converter" using a transimpedance amplifier. This takes the current output from the Electrochemical Cell and changes it into a voltage that can be read and recorded by the Microcontroller.