Multimeter Filtered Measurement Mode Rotary Switch
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Solution Overview
Problem
Existing multimeters face difficulties in making accurate measurements in complex environments like adjustable speed motor drives, uninterruptible power sources, and switching power supplies due to high-frequency noise and distortion, requiring a more convenient low-pass filtering mode to filter out unnecessary high-frequency components.
Innovation Solution
A multimeter with a filtered measurement mode incorporating a signal conditioning circuit, low-pass filter, microprocessor, RMS converter, display unit, and external rotary switch, where the rotary switch enables low-pass filtering mode selection without the need for visual indicators, simplifying operation by generating a control signal to communicate with the RMS converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single button is used to select low-pass filtering mode, then the device complexity is reduced, but the ease of operation deteriorates because users must carefully check visual indicators to avoid misoperation
Solution Approach 1:
The patent replaces the mechanical button-press interface with a rotary switch mechanism. The rotary switch provides tactile mechanical feedback through distinct positioning stops, allowing users to sense the filtering mode engagement physically without needing to visually check indicators. This mechanical substitution resolves the contradiction by maintaining simple device structure while dramatically improving ease of operation through intuitive tactile feedback.
2Reliability
If visual indicators are used to show filtering mode status, then the reliability of mode selection is improved, but the ease of operation deteriorates due to the need to check symbols before operation
Solution Approach 1:
The rotary switch serves itself by providing inherent tactile feedback that indicates the current mode without requiring external visual indicators. The mechanical structure of the rotary switch creates distinct positional sensations that automatically inform the user of the filtering state, eliminating the need for separate display elements and reducing operational steps.
3Ease of operation
If a rotary switch is used to control filtering mode, then the ease of operation is improved through intuitive selection, but the device complexity increases compared to a single button
Solution Approach 1:
The rotary switch is designed to serve multiple functions: it selects between different measurement ranges (AC/DC voltage, current, resistance) and controls the filtering mode engagement. This multi-functionality consolidates what could be multiple separate controls into a single universal interface, improving ease of operation while minimizing the actual increase in 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
This configuration simplifies the operation of low-pass filtering, allowing users to easily select and engage the filtered measurement mode, reducing the risk of misoperation and ensuring accurate measurements by eliminating the need to check for visual symbols, thus providing a more user-friendly and accurate measurement process.
Implementation Method 1
a low-pass filter, installed in the multimeter, is used to filter out unnecessary high-frequency component of the voltage signal to acquire correct RMS voltage value
Data Source
AI summary
A multimeter with filtered measurement mode is disclosed. The multimeter includes a signal conditioning circuit, a low-pass filter, a microprocessor, a measurement circuit, a root-mean-square (RMS) converter, a display unit, and an external rotary switch. The signal conditioning circuit receives a control signal to select an operation mode of the multimeter. The low-pass filter is electrically connected to the signal conditioning circuit. The microprocessor is electrically connected to the signal conditioning circuit. The measurement circuit is electrically connected to the microprocessor and the RMS converter to measure a signal outputted from the RMS converter. The display unit is electrically connected to the microprocessor and the measurement circuit. Also, the external rotary switch is optionally connected to the microprocessor. Whereby rotating the external rotary switch to generate the control signal and perform a low-pass filtering mode to communicate the low-pass filter with the RMS converter.