Replaceable Probe Head With Operational Amplifier
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Solution Overview
Problem
Existing probes with sensors, especially those used underwater, face issues where the entire probe needs to be discarded when the sensor fails, leading to wastage of expensive circuit boards and electronics, and water ingress at the probe head-probe body connection causes detrimental shifts in sensor readings due to low impedance.
Innovation Solution
A replaceable probe head with a working electrode and operational amplifier between the electrode and electrical connector, which provides stable sensor readings by electrically isolating high impedance signals from low impedance interconnects, allowing the probe body to be reused and maintaining a watertight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire probe is discarded when the sensor dies, then the sensor can be replaced, but the expensive circuit board and electronics are wasted
Solution Approach 1:
The probe is divided into two separable parts: a disposable probe head containing the sensor and a reusable probe body containing the circuit board and electronics. This segmentation allows the sensor to be replaced without discarding the expensive electronic components, directly resolving the contradiction between sensor replacement and electronic waste.
2Ease of repair
If the probe head is removeably connectable to the probe body, then the probe head can be replaced, but water can access the connection causing low impedance and detrimental shifts in sensor readings
Solution Approach 1:
An operational amplifier is introduced as an intermediary component between the sensor and the electrical connector. This intermediary provides electrical isolation through its high input impedance, preventing water ingress at the connector from causing low impedance paths that would otherwise destabilize sensor readings, thus maintaining reliability while allowing replaceability.
3Ease of operation
If water is present at the probe head to probe body connection, then the connection remains simple, but the current flow experiences low impedance creating detrimental shifts in sensor readings
Solution Approach 1:
The operational amplifier serves as an electrical intermediary that isolates the high-impedance sensor signals from the low-impedance interconnect formed by water at the connector. This intermediary protection maintains measurement precision without requiring complex waterproofing, preserving ease of operation.
4Reliability
If the operational amplifier is added within the probe head, then the sensor readings become stable, but the device complexity increases
Solution Approach 1:
The operational amplifier is extracted and placed within the disposable probe head rather than the reusable probe body. This extraction allows the complexity of the operational amplifier to be confined to the low-cost, replaceable probe head, while the expensive probe body remains relatively simple and reusable, making the increased complexity acceptable.
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
Enables the reuse of the probe body's electronics while providing stable sensor readings by isolating high impedance signals from low impedance interconnects, reducing waste and maintaining accuracy even in underwater conditions.
Implementation Method 1
the addition of an operational amplifier within the probe head between the working electrode and the electrical connector successfully electrically isolates the high impedance signals in the probe head from the low impedance interconnect
Data Source
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AI summary
A detachable, replaceable, and/or disposable probe head connectable to a probe body containing electronics, a probe that includes the probe head and the probe body, and the combination of a sonde and the probe are described herein. The probe head includes a housing that has a coupling member for detachably connecting the housing to the probe body, in particular to the electronics in the probe body. The probe head also includes a sensor and an electrical connector at least partially housed within the housing, and an operational amplifier electrically coupling the sensor to the electrical connector.