Electrochemical Measurement Circuit with High-Capacitance Feedback

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Solution Overview

Problem

Electrochemical measurement systems face challenges in accurately detecting and quantifying substances due to noise interference from external and internal sources, which can mask minute currents generated by chemical or biochemical reactions, especially at low concentrations.

Innovation Solution

The system incorporates a capacitor with a capacitance of 1 µF or greater connected between the operational amplifier's output and the counter electrode, along with a switch and buffer circuit, to reduce noise and improve measurement accuracy by enhancing the feedback loop's noise reduction capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional three-electrode measurement system is used, then the measurement can be performed with standard components, but noise from external and internal sources interferes with the detection of minute currents

Engineering Contradiction:
Improvedetection accuracy of minute currentsVSAvoidnoise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a capacitor as an intermediary component connected between the counter electrode and the solution. This capacitor acts as a noise filter that blocks high-frequency noise signals while allowing the measurement of minute currents generated by chemical reactions, thereby improving the signal-to-noise ratio without affecting the core measurement function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback circuit that continuously monitors the potential at the reference electrode and adjusts the voltage applied to the counter electrode accordingly. This feedback mechanism compensates for potential drift and noise interference, maintaining stable measurement conditions and improving detection precision

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the capacitance of the capacitor is increased to reduce noise, then noise reduction capability is improved, but the circuit complexity increases

Engineering Contradiction:
Improvenoise levelVSAvoidcircuit configuration
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent specifies a capacitor with a capacitance of 1 µF or greater, establishing a clear parameter threshold that balances noise reduction effectiveness with circuit simplicity. By defining this specific capacitance value, the patent achieves optimal noise filtering without requiring complex circuit configurations or multiple capacitor stages

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively reduces noise, particularly thermal and flicker noise, allowing for more accurate measurement of minute currents and improving the detection of substances at low concentrations, thereby enhancing the overall precision of electrochemical measurements.

Implementation Method 1

a capacitor having a capacitance of 1 μ F or greater; wherein the capacitor is connected to the output of the operational amplifier (OUT) and the counter electrode (CE) at one end, and connected to the output terminal of the switch circuit at the other end

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3779426B1Device for an electrochemical measurement of a solution
Publication Date: 2023.12.27 PROVIGATE KK
  • EP3779426B1 patent drawingFigure 1
  • EP3779426B1 patent drawingFigure 2
  • EP3779426B1 patent drawingFigure 3

AI summary

Provided is an electrical circuit for electrochemical measurement of a solution, said electrical circuit comprising: a voltage generation circuit; an operational amplifier that has an output (OUT), a non-inverting input (+IN), and an inverting input (-IN), wherein the output (OUT) is connected to a counter electrode (CE) in contact with the solution, the inverting input(-IN) is connected to a reference electrode (RE) in contact with the solution, and the non-inverting input (+IN) is connected to the voltage generation circuit; a capacitor that is connected between the output (OUT) and inverting input (-IN) and has a capacitance of 1 µF or greater; and a current measurement circuit that is connected to a working electrode (WE) in contact with the solution.