Potentiometric Measuring Device Unipolar Supply Voltage Adaptation
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Solution Overview
Problem
Existing potentiometric measuring devices for determining ion concentrations and redox potential in liquids face limitations due to symmetrical voltage requirements, limited measuring ranges, and interference issues, especially with unipolar supply voltages, which restrict their operational flexibility and accuracy.
Innovation Solution
A measuring device with a setting circuit that dynamically adjusts the reference electrode's potential within the unipolar supply voltage range, allowing for maximum measuring range adaptation and separate impedance measurement using a single AC voltage signal, integrated with a microcontroller for efficient operation and interference management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a symmetrical voltage circuit is used to compensate interference potentials, then the measuring range is extended, but the supply voltage range requirement increases severely
Solution Approach 1:
The patent applies asymmetry by using a unipolar supply voltage (0 to +3V) instead of a symmetrical bipolar supply voltage. The reference electrode potential is adjusted asymmetrically within the unipolar range to compensate for interference potentials, allowing the measuring circuit to operate with a single polarity supply while maintaining extended measuring capability through dynamic reference potential adjustment.
Solution Approach 2:
The patent changes the parameter of reference electrode potential dynamically within the unipolar supply voltage range. By adjusting the reference potential parameter adaptively based on interference conditions, the circuit achieves extended measuring range without requiring a larger supply voltage range, thus resolving the contradiction between adaptability and energy consumption.
2Measurement precision
If the reference electrode potential is fixed to extend measuring range, then measurement accuracy improves, but the circuit complexity increases
Solution Approach 1:
The patent implements self-service by using the microcontroller's internal resources (DAC or voltage divider circuit) to generate and adjust the reference electrode potential without requiring external complex circuitry. The microcontroller automatically manages the reference potential adjustment based on measured interference, simplifying the overall circuit while maintaining measurement precision.
3Reliability
If separate impedance measurements are implemented, then diagnostic capability improves, but the measurement time increases
Solution Approach 1:
The patent applies periodic action by implementing impedance measurements at specific intervals during the potentiometric measurement process. The microcontroller periodically switches between voltage mode (for potential measurement) and impedance mode (for diagnostic measurements), allowing comprehensive monitoring without continuous impedance measurement, thus balancing diagnostic capability with measurement time efficiency.
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
The solution enables extended measuring ranges without altering circuit elements, accounts for interference potentials, and operates effectively with low internal supply voltages, supporting various electrochemical measurements, including pH and redox potentials, while maintaining low energy consumption and circuit simplicity.
Implementation Method 1
The pH value of the measuring liquid or another ion concentration or the redox potential is determined by measuring the potential difference between the measuring and reference electrodes
Implementation Method 2
the reference electrode is coupled purely capacitively to a reference potential. Interference voltages are thus discharged with low resistance via the capacitance
Data Source
Figure 1~2
Figure 3~4
AI summary
The device (1) has measuring electrode (3) and reference electrodes (4,5) that are immersed in a measuring liquid (2). Input ends of a measuring circuit are coupled to measuring electrode (3) and reference electrode (4), for providing stationary signal relating electrochemical measuring variable. Electrical potential at reference electrode (5) is adjusted variably within the range of the unipolar supply voltage, by connecting with a low resistor, and the measuring electrode (3) and the reference electrode (4) are capacitively coupled to a reference mass. An independent claim is included for method for potentiometric determination of electrochemical measurement parameters in measuring liquid.