Capacitance Measurement Device Using Ground-Referenced Potential
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Solution Overview
Problem
Conventional capacitance measurement devices face challenges in achieving high accuracy and fast measurement rates due to noise interference and the use of current measurements, which are affected by small current values and indefinite potential differences between capacitances.
Innovation Solution
A capacitance measurement device that discharges the potential between two capacitances to a ground reference, allowing for accurate measurement of the measurement-objective capacitance by measuring the potential between them, using a bridging capacitor and a charging/discharging switching element to calibrate and charge the capacitance, thereby reducing noise interference and enabling fast and accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurement method is used to measure capacitance, then capacitance can be measured, but measurement precision deteriorates due to noise interference and small current values
Solution Approach 1:
The patent replaces the electrical current measurement method with a voltage measurement method. Instead of measuring the small current flowing through the capacitance, the invention measures the voltage at the intermediate potential point between the measurement capacitance and reference capacitance. This substitution of measurement parameter from current to voltage eliminates the noise interference problem that affects small current measurements, thereby improving measurement precision.
2Measurement precision
If voltage measurement method is used without ground reference, then capacitance can be calculated, but measurement precision deteriorates due to indefinite potential
Solution Approach 1:
The patent applies the equipotentiality principle by establishing a ground reference potential. The potential measurement point is defined relative to ground, creating a stable reference level. This grounds the intermediate potential between the measurement capacitance and reference capacitance, transforming the indefinite potential into a stable, measurable voltage value that can be accurately converted to capacitance.
3Measurement precision
If conventional capacitance measurement device is used, then capacitance can be measured, but device complexity increases due to complicated circuit configuration
Solution Approach 1:
The patent extracts and eliminates unnecessary circuit components from conventional capacitance measurement devices. By using a simple voltage measurement approach with ground reference, the invention removes the need for complex current measurement circuits, multiple switching elements, and complicated signal processing circuits, thereby simplifying the overall device structure while maintaining high measurement precision.
4Measurement precision
If charging time is extended to store electricity in capacitor, then capacitance measurement can be performed, but productivity deteriorates due to slow measurement rate
Solution Approach 1:
The patent employs periodic action by using alternating voltage applied to the reference capacitance. This periodic voltage causes periodic charging and discharging of the measurement capacitance through the switching element, allowing the system to perform multiple measurements in quick succession. The periodic nature enables fast measurement rates while maintaining precision through repeated sampling and averaging.
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 highly accurate and fast capacitance measurements by stabilizing the intermediate potential at a ground reference, reducing noise interference and allowing for precise calculation of capacitance values, even in the presence of noise, and facilitates calibration for improved measurement reliability.
Implementation Method 1
a capacitance measurement device that discharges the potential between two capacitances to a ground reference
Implementation Method 2
allowing for accurate measurement of the measurement-objective capacitance by measuring the potential between them
Data Source
AI summary
A capacitance measurement device includes a bridging capacitor connected in series to another one of the opposite end sides of a measurement-objective capacitance, and a charging/discharging switching element connected in series to the other one of the opposite end sides of the measurement-objective capacitance, and connected in parallel to the bridging capacitor. The measurement-objective capacitance is discharged when the charging/discharging switching element is turned to the closed state, and is charged when the charging/discharging switching element is turned to the opened state. A gauge gains an equivalent value for the measurement-objective capacitance, based on a potential at the other one of the opposite end sides of the measurement-objective capacitance, at the time of the charging step.