similarity-resistor

# Resistor Similarity Calculator Skill Guidance for working with `ResistorSimilarityCalculator` in the lib-electronic-components library. --- **For metadata-driven similarity architecture**, see `/similarity-metadata`: - SpecImportance levels (CRITICAL, HIGH, MEDIUM, LOW, OPTIONAL) - ToleranceRule types (exactMatch, percentageTolerance, minimumRequired, etc.) - SimilarityProfile contexts (DESIGN_PHASE, REPLACEMENT, COST_OPTIMIZATION, etc.) - Calculator integration patterns and gotchas --- ## Overview The `ResistorSimilarityCalculator` compares resistors based on: - **Package size** (0.3 weight) - 0402, 0603, 0805, etc. - **Resistance value** (0.5 weight) - 10K, 100R, 4.7K, etc. Maximum similarity is 0.8 (not 1.0) since tolerance and other specs aren't always extractable. ## Applicable Types ```java ComponentType.RESISTOR ComponentType.RESISTOR_CHIP_VISHAY ComponentType.RESISTOR_CHIP_YAGEO ComponentType.RESISTOR_CHIP_PANASONIC ComponentType.RESISTOR_CHIP_BOURNS // Any type starting with "RESISTOR_" ``` ## Similarity Scoring | Condition | Score | |-----------|-------| | Same value, same package | 0.8 | | Same value, different package | 0.5 | | Same package, different value | 0.3 | | Different value, different package | 0.0 | ## Value Extraction The calculator extracts resistance values from MPNs: | MPN | Extracted Value | |-----|-----------------| | `CRCW060310K0FKEA` | 10K (10kΩ) | | `RC0603FR-0710KL` | 10K (10kΩ) | | `ERJ3GEYJ103V` | 10K (103 = 10×10³) | ## Package Size Extraction Common package codes in MPNs: | Pattern | Package | |---------|---------| | `0603` | 0603 (1608 metric) | | `0805` | 0805 (2012 metric) | | `1206` | 1206 (3216 metric) | ## Cross-Manufacturer Matching The calculator can match equivalent resistors across manufacturers: ```java // Vishay 0603 10K vs Yageo 0603 10K calculator.calculateSimilarity("CRCW060310K0FKEA", "RC0603FR-0710KL", registry); // Returns >= 0.5 (both are 10K, may have same package) ``` ## Test Examples ```java // Same Vishay resistor - max similarity calculator.calculateSimilarity("CRCW060310K0FKEA", "CRCW060310K0FKEA", registry); // Returns 0.8 // Same value, different package calculator.calculateSimilarity("CRCW060310K0FKEA", "CRCW080510K0FKEA", registry); // Returns 0.5 // Same package, different value calculator.calculateSimilarity("CRCW0603100RFKEA", "CRCW060310K0FKEA", registry); // Returns 0.3 (100R vs 10K) ``` ## Implementation Notes - Returns 0.0 for null MPNs or null registry - Returns 0.0 for empty strings - Handles unrecognized formats gracefully (returns 0.0-1.0) --- ## Learnings & Quirks ### Value Notation - E96 notation: `103` = 10×10³ = 10kΩ, `4R7` = 4.7Ω - Yageo TCR code `-07` is NOT a separator, it's temperature coefficient ### Package Extraction - Some MPNs embed package in series name (e.g., `RC0603`) - Others have separate position (e.g., `CRCW` + `0603`) <!-- Add new learnings above this line -->