Digital Multimeter Self-Test Circuit for Safety Component Detection
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Solution Overview
Problem
Existing digital multimeters lack internal self-check functions to test the functionality of safety-related components, posing a risk to users when used in harsh measurement environments, especially for high voltages or currents.
Innovation Solution
Integration of self-test functions within the digital multimeter circuitry that automatically check the status of safety components like PTC thermistors, RC series circuits, and resistive voltage dividers, using a controller to form test paths and analyze electrical properties for proper functioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-test functions are integrated into the digital multimeter, then reliability is improved, but device complexity increases
Solution Approach 1:
The digital multimeter performs self-diagnosis by automatically testing safety components (PTC thermistor, RC series circuit, resistive voltage divider) without requiring external test equipment. The controller forms test paths, applies test signals, and analyzes electrical properties to detect dysfunctions, enabling the device to monitor its own safety status.
Solution Approach 2:
The self-test function is activated before actual measurement operations to verify that safety components are functioning properly. This preliminary checking prevents potential safety issues from arising during subsequent measurement tasks, ensuring the multimeter is in a safe state before use.
2Reliability
If safety components are added to protect users, then reliability is improved, but device complexity increases
Solution Approach 1:
The controller continuously monitors the electrical state of safety components during self-test operations and provides feedback about their functionality. By analyzing electrical properties such as resistance and voltage, the system determines whether safety components are operating correctly and can alert users to potential issues.
Solution Approach 2:
The self-test function is divided into separate test modules, each dedicated to testing a specific safety component (PTC thermistor, RC series circuit, resistive voltage divider). This segmentation allows independent testing of each component without affecting the entire circuit system.
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
Ensures the safety and reliability of the digital multimeter by detecting dysfunctions in safety components, preventing dangerous misconnections and ensuring accurate measurements.
Implementation Method 1
There are some safety components on the printed circuit assembly of a DMM. The safety components are configured to protect users or the DMM in different measurement situations, e.g., where excessive voltages are applied to the measurement terminals.
Data Source
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AI summary
A tester (100) includes self-test functions to test a state of a measurement circuit in the tester. For example, the self-test functions test an electrical state, e.g., electrical properties or connection or disconnection states, of a component of the measurement circuit. The self-test functions also test the signal state of an electrical component in the measurement circuit, which may include signal detection, signal transmittance, or measurement properties of the electrical component. The self-test functions improve the user experience of the tester from safety and reliability perspectives.