Kelvin Continuity Checker With Calibrated Resistance Threshold
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Solution Overview
Problem
Existing electrical continuity checkers do not provide specific resistance value measurements, failing to ensure connections meet design specifications, and calibrated ohmmeters lack pass/fail thresholds.
Innovation Solution
A calibrated continuity checker incorporating a precision reference resistor compares the resistance of an unknown to a set threshold, using a four-wire Kelvin probe to eliminate lead resistance and provide a binary pass/fail indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a basic continuity checker is used, then the device simplicity and ease of operation are improved, but the measurement precision and ability to verify resistance specifications are lost
Solution Approach 1:
A precision reference resistor is introduced as an intermediary element to enable calibrated resistance measurement. The reference resistor serves as a known standard against which unknown resistances are compared, allowing the device to provide both pass/fail indication and actual resistance measurement capability
Solution Approach 2:
The patent replaces simple continuity detection (binary on/off) with an electrical measurement system that uses a precision reference resistor and measurement circuitry to determine actual resistance values, thereby substituting basic mechanical/electrical switching with precision electrical measurement
2Measurement precision
If a calibrated ohmmeter is used, then the measurement precision is improved, but the device complexity increases and pass/fail threshold indication is lost
Solution Approach 1:
The measurement function is segmented into two distinct modes: calibrated measurement mode (using the precision reference resistor for accurate resistance measurement) and pass/fail indication mode (comparing measured resistance against a threshold). This segmentation allows the device to provide both measurement precision and operational simplicity for different use cases
Solution Approach 2:
The device dynamically switches between different measurement and indication modes based on the testing requirements. The system can toggle between providing detailed resistance measurements and providing simple pass/fail indications, adapting its output based on the specific testing scenario
3Device complexity
If test lead resistance is not compensated, then the device complexity is reduced, but the measurement precision deteriorates due to varying lead lengths
Solution Approach 1:
A calibration cycle is implemented as a preliminary action before actual measurements. During calibration, the system characterizes and stores the resistance of the test leads, which is then used to compensate for lead resistance during subsequent measurements, ensuring accurate results regardless of lead length variations
Solution Approach 2:
The system uses feedback from the calibration process to automatically adjust for test lead resistance. The measured lead resistance from calibration is fed back into the measurement calculation, allowing the device to compensate for lead effects without requiring manual intervention or complex user procedures
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 electrical connections meet resistance specifications by providing precise resistance measurements and clear pass/fail indicators, eliminating the need for calibration cycles.
Implementation Method 1
In various embodiments, it is possible to utilize four-wire (Kelvin) probes, such that the resistance of the probe wire is not included in the measured value.
Implementation Method 2
A device which combines the simplicity of a pass/fail style continuity checker with the parametric measurement capability of a resistance meter is provided herein. Various embodiments described herein provide such a calibrated continuity checker by incorporating a precision reference resistor that is compared to the unknown to determine if the resistance value of the unknown is greater than, equal to, or less than the pass/fail threshold.
Data Source
AI summary
A continuity detector for determining the continuity of a Unit Under Test (UUT). The detector comprises a housing defining an interior volume, an electronics package disposed within the interior volume defined by the housing assembly, a first test contact and a second test contact to interface with the electrical wire or harness assembly, a precision resistance standard disposed within the housing and electrically coupled to the electronics package, and a power source disposed within the housing assembly. The first test contact and the second test contact are external to the interior volume. The first test contact and the second test contact are electrically coupled to the electronics package. The electronics package comprising a resistance measurement device and a comparator circuit. The comparator circuit is configured to determine if the resistance of the UUT is greater than, less than, or equal to the resistance of the resistance standard.