Arrangement for Measuring Capacitance

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This invention provides an electronic arrangement for accurately measuring the capacitance of a measurement capacitor, particularly in scenarios where the capacitance is influenced by external factors such as soil humidity. The arrangement uses a first circuit with at least two diodes and the measurement capacitor, connected in a way that enables controlled charging and discharging without the need for complex switching mechanisms. A second circuit, typically including a delta-sigma modulator and filtering mechanisms, translates the resulting electrical signals into precise capacitance measurements, making it robust for a wide range of values.

Use CasesContent extracted from patent full text and abstract with AI.

• Soil moisture sensors for agricultural or environmental monitoring, where soil humidity affects capacitance.
• Industrial humidity monitoring in air, gases, or other substances, using capacitive sensing.
• Quality control in manufacturing environments that rely on detecting moisture or dielectric changes.
• Smart irrigation systems that adjust water supply based on real-time soil moisture measurements.
• Consumer electronics or IoT devices that monitor ambient environmental conditions (e.g. smart plant pots, greenhouse monitoring).
• Scientific research applications requiring precise measurement of variable capacitance due to environmental effects.

BenefitsContent extracted from patent full text and abstract with AI.

• Provides precise and robust capacitance measurement over a wide range of values, including extreme humidity changes.
• Eliminates the need for complex or bulky switching circuits by using diode-based charging and discharging, reducing circuit complexity and cost.
• Minimizes noise and error sources associated with switch-based circuits (such as clock feed-through and switching glitches).
• Allows sensitivity and precision improvements by extending measurement intervals and digital filtering, enabling adaptable resolution for differing applications.
• Can be implemented with standard, cost-effective electronic components and is easily integrable into digital systems (via delta-sigma modulator).
• Reduces overall failure points and enhances reliability compared to traditional switch-based capacitive measurement circuits.

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

The present invention is in the field of measuring capacitance of a measurement capacitor C. The measured capacitance can depend on humidity, for example on the humidity of soil. An arrangement for measuring the capacitance includes a first circuit and a second circuit, wherein the second circuit is adapted to provide a signal corresponding to the capacitance of the measurement capacitor C based on a signal provided by the first circuit system. More specifically, the first circuit includes at least two diodes connected in series, wherein a first port of the measurement capacitor C is connected to the contact between two of the diodes connected in series and a second port of the measurement capacitor C is connected to a signal line.