Gas Sensor Offset Voltage Amplification for Measurement Accuracy
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Solution Overview
Problem
Existing gas detecting apparatuses face limitations in measurement accuracy due to low input resolution and the need for high-resolution arithmetic circuits, which increase costs and restrict amplification factors, making it difficult to achieve high measurement accuracy for small voltage changes in gas concentration or humidity detection.
Innovation Solution
A gas detecting apparatus that uses a heating resistor controlled at two different temperatures, with offset voltages subtracted from output voltages to amplify potential differences, allowing for high amplification factors even with low-cost electronic controllers, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution arithmetic circuit is used to detect small voltage changes, then measurement accuracy is improved, but device cost increases
Solution Approach 1:
The patent applies preliminary action by performing voltage amplification before the arithmetic circuit processes the signal. The amplifier circuit is positioned between the heating resistor and the arithmetic circuit, pre-amplifying the small voltage changes to a larger range. This allows the subsequent arithmetic circuit to operate with standard resolution settings while still achieving high measurement accuracy, thereby avoiding the need for an expensive high-resolution arithmetic circuit.
2Measurement precision
If the output voltage is directly inputted to the arithmetic circuit, then device complexity is reduced, but measurement accuracy becomes low due to limited voltage resolution
Solution Approach 1:
The patent introduces an intermediary component - the amplifier circuit - between the heating resistor and the arithmetic circuit. This amplifier circuit acts as a mediator that takes the small voltage changes from the heating resistor and transforms them into larger voltage signals suitable for standard arithmetic circuit processing. The amplifier circuit includes voltage multiplication components that systematically enhance the signal magnitude without requiring complex high-resolution arithmetic processing.
3Measurement precision
If voltage amplification is applied to increase measurement accuracy, then measurement accuracy is improved, but the amplification factor is limited by power supply voltage constraints
Solution Approach 1:
The patent applies segmentation by dividing the amplification process into multiple stages rather than relying on a single high-gain amplifier. The circuit includes multiple amplifier sections that each provide moderate voltage multiplication, with the cumulative effect achieving the desired total amplification factor. This segmented approach allows the system to achieve high measurement accuracy while keeping individual amplifier stages manageable and the overall circuit design practical within standard power supply constraints.
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 apparatus achieves high measurement accuracy for gas concentration and humidity detection by setting large amplification factors, even with low-cost devices, simplifying control and reducing circuit complexity while maintaining cost-effectiveness.
Implementation Method 1
a sensor for measuring humidity using a change in thermal radiation from a temperature measurement resistor heated by a heating element for self-heating by Joule heat
Implementation Method 2
a sensor for measuring humidity using a change in thermal radiation from a temperature measurement resistor heated by a heating element
Data Source
AI summary
A gas detecting apparatus including: a heating resistor exposed to a detected atmosphere, and a control circuit for controlling the heating resistor at two different temperatures, wherein each output voltage from the heating resistor corresponding to the different temperatures is detected when the heating resistor is controlled to the different temperatures, and a state of a gas is obtained based on the detected output voltage. For example, two different offset voltages are set, each potential difference obtained by subtracting each of the offset voltages from corresponding detected output voltages is amplified and the state of the gas is obtained using the amplified potential differences.