Digital pH Sensor Impedance Transformation for Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modifying digital pH sensors with inexpensive components can lead to poor measurement performance, incorrect temperature sensing, loss of safety features, and errors in calculation and diagnostic functions, compromising safety and accuracy.
Innovation Solution
A digital pH sensor design with an electronics unit and two half-cells, where the electrolytes and electrodes are selected to create a non-zero potential difference at pH 7 and 25°C, allowing the electronics unit to convert this into a digital measured value, ensuring safety conditions are met and enabling warnings or protections against safety risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pH sensors are modified with inexpensive components to reduce cost, then manufacturing cost is reduced, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent changes the electrical parameters of the sensor system by introducing an impedance transformation stage that converts the high-impedance millivolt signal from the pH electrode into a low-impedance voltage signal. This parameter transformation allows the use of simpler, more inexpensive electronic components while maintaining measurement precision, as the transformed signal is less susceptible to interference and can be processed by standard electronic circuits.
2Reliability
If complex impedance transformation stages are added to handle high sensor impedance, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex passive impedance matching networks with an active electronic impedance transformation stage using operational amplifiers. This substitution simplifies the overall device architecture by using standard electronic building blocks rather than complex passive component arrangements, thereby improving reliability while controlling device complexity.
3Device complexity
If standard pH electrode configurations are used to maintain simplicity, then device complexity is reduced, but susceptibility to electromagnetic interference increases
Solution Approach 1:
The patent introduces an intermediary impedance transformation stage between the high-impedance pH electrode and the subsequent electronic circuits. This intermediary stage acts as a buffer that isolates the electrode from electromagnetic interference while transforming the signal to a level that can be processed by standard electronic components, thus protecting against harmful electromagnetic effects without significantly increasing device 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
The digital pH sensor ensures safe measuring operations by allowing users to detect and prevent safety risks associated with incorrect measured values, maintaining accurate measurements and safety features.
Implementation Method 1
The first half-cell and the second half-cell form a potential difference between the first electrode and the second electrode if the digital pH sensor is in contact with a measurement medium
Implementation Method 2
The second half-cell, the so-called 'reference half-cell,' is in contact with the measurement medium via an electrochemical junction, which allows for limited ion exchange, and thus ion conduction, between the reference electrolyte and the measurement medium
Data Source
AI summary
Disclosed is a digital pH sensor for measuring the pH, comprising an electronics unit, sensor housing having a first half-cell and a second half-cell adapted to form a potential difference between the first electrode and the second electrode if the digital pH sensor is in contact with a measurement medium, wherein the electronics unit is adapted for converting the potential difference into a digital voltage value or a digital pH value, wherein the first electrolyte, the first electrode, the second electrolyte, and/or the second electrode are selected such that, at a pH value of 7 and a temperature of 25° C. in the measurement medium, the potential difference of the two electrodes is not equal to 0 mV, and wherein the electronics unit converts the potential difference into the digital measured pH value of 7 or a digital measured voltage value of 0 mV.