Diode Checker Using Multimeter and Voltage Divider
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Solution Overview
Problem
Existing diode testing equipment is expensive and inefficient for matching diodes in low-current environments, particularly in flight testing scenarios where diodes often fail due to voltage and current spikes, and require precise matching within a narrow amperage range.
Innovation Solution
A diode checker device utilizing a combination of standard multimeters, voltage dividers, and rotary switches to adjust resistance, allowing for precise matching of diodes within a 40 to 90 microamps range, using a linear circuit with resistors and a DC voltmeter to bias the diode and adjust current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized test equipment is used to test diodes, then measurement precision and reliability are improved, but device cost increases significantly
Solution Approach 1:
The specialized test equipment is segmented into standard components: a multimeter is divided into voltage measurement mode and current measurement mode, with the current measurement function achieved through a combination of voltage divider circuit and rotary switch. This segmentation allows using common, inexpensive multimeters instead of expensive specialized equipment while maintaining measurement precision.
Solution Approach 2:
The multimeter is made multi-functional by adding external circuitry (voltage divider and rotary switch) to enable current measurement capability. The same multimeter can measure both voltage directly and current through the added circuit, eliminating the need for separate specialized test equipment and reducing overall device complexity and cost.
2Device complexity
If standard multimeters are used without modification, then device cost is reduced, but measurement precision for low-current diode testing deteriorates
Solution Approach 1:
A voltage divider circuit acts as an intermediary between the standard multimeter and the diode under test. The voltage divider transforms the small current through the diode into a measurable voltage drop, which the standard multimeter can then measure with its high-precision voltage measurement capability, thereby maintaining measurement precision for low-current applications.
Solution Approach 2:
The measurement parameter is changed from direct current measurement to voltage measurement through the voltage divider. By measuring the voltage drop across a known resistance in series with the diode and calculating current from Ohm's law, the system achieves precise low-current measurement using standard multimeter voltage measurement capabilities.
3Ease of operation
If resistance adjustment is not provided, then device complexity is reduced, but adaptability for matching diodes within narrow amperage range deteriorates
Solution Approach 1:
The circuit incorporates a rotary switch that dynamically changes the resistance configuration, allowing the user to adjust the current range for different diode matching requirements. This dynamic adjustment capability provides adaptability for matching diodes within narrow amperage ranges while using simple, discrete circuit components rather than complex electronic controls.
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
Enables cost-effective and efficient diode matching in low-current environments, reducing equipment costs and improving reliability in flight testing by allowing precise adjustment of diode amperage, thereby extending diode lifespan and maintaining system performance.
Implementation Method 1
A diode checker device utilizing a combination of standard multimeters, voltage dividers, and rotary switches to adjust resistance, allowing for precise matching of diodes within a 40 to 90 microamps range
Implementation Method 2
using a linear circuit with resistors and a DC voltmeter to bias the diode and adjust current levels
Data Source
AI summary
Embodiments of the invention are directed to using a DC multimeter configured for checking device amperage. A DC voltmeter is electrically-connected in series with the DC multimeter. A linear circuit is electrically connected in series between the DC multimeter and the DC voltmeter. A device under test is electrically-connected between positive and negative terminals of the DC voltmeter.