Electrochemical Sensor Reference Electrode Segmentation for Low-Voltage Interference Rejection
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Solution Overview
Problem
Existing electrochemical measuring devices face limitations due to high supply voltage requirements and interference issues, particularly with modern unipolar supply voltages, and lack separate impedance measurement capabilities for reference and measuring electrodes.
Innovation Solution
A capacitive connection of the reference electrode to the reference ground with high-impedance fixing to a fixed potential allows for interference discharge and separate impedance measurement, enabling accurate and interference-resistant electrochemical parameter measurement with reduced supply voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a symmetrical wiring with direct reference electrode connection to reference ground is used, then interference voltages can be discharged well, but the supply voltage range must be greater than the sum of voltage values between reference and reference electrodes
Solution Approach 1:
The patent segments the reference electrode connection into two independent paths: a low-impedance path to reference ground for interference discharge, and a high-impedance path to the fixed potential point for voltage reference. This segmentation allows the reference electrode to simultaneously discharge interference voltages while operating within a reduced supply voltage range.
Solution Approach 2:
The patent introduces a capacitor as an intermediary element between the reference electrode and reference ground. This capacitor enables AC interference signals to be discharged while blocking DC voltage shifts, allowing the reference electrode to maintain a stable DC operating point within the reduced supply voltage range while still providing interference discharge capability.
2Use of energy by moving object
If asymmetrical wiring with reference electrode connected to reference ground is used, then supply voltage range is reduced, but interference voltages cannot be discharged and impedance measurement is not possible
Solution Approach 1:
The patent segments the reference electrode connections into functionally independent paths: one dedicated to interference discharge (low-impedance to reference ground) and another dedicated to voltage reference (high-impedance to fixed potential point). This segmentation enables the system to achieve both reduced supply voltage requirements and maintained interference resistance.
Solution Approach 2:
The reference electrode serves multiple functions simultaneously through the segmented connection architecture: it provides interference discharge through the low-impedance path, maintains a stable voltage reference through the high-impedance path, and enables both pH measurement and impedance measurement of electrodes. This multi-functionality is achieved without requiring separate dedicated electrodes for each function.
3Measurement precision
If separate impedance measurement of reference and measuring electrodes is required, then additional measurement circuits are needed, but this increases device complexity
Solution Approach 1:
The patent enables the existing reference electrode connection architecture to serve dual purposes: the high-impedance connection path used for maintaining voltage reference also serves as the measurement path for impedance determination. By measuring the voltage at the fixed potential point during impedance measurement mode, the system can determine electrode impedance without requiring separate dedicated measurement circuits, thus avoiding additional complexity.
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 solution enables accurate measurement of electrochemical parameters with a small unipolar supply voltage, allowing for separate impedance measurement of electrodes and covering a wide measuring range without adding to the redox voltage, simplifying equipment and reducing circuit complexity.
Implementation Method 1
The reference electrode is connected in a purely capacitive manner to the reference ground of the measuring circuit via a capacitor
Data Source
Figure 1~4
AI summary
The device has a measuring electrode (4), reference electrode (5) and a supply electrode (6), where all the three electrodes are dipped into measuring liquid. A measuring circuit (7) has an input circuit (8, 9) that is connected with the measuring and/or reference electrodes. The measuring circuit has a subtractor (10) that forms a differential signal that represents electrochemical quantities, which are to be measured. A ground reference is capacitively coupled with the supply electrode, and the reference electrode is high-resistively fixed on a fixed potential. An independent claim is also included for a method such as a redox-potential measuring method for measuring electrochemical quantities in liquid.