Voltage Regulator Similarity Calculator Skill

Guidance for working with VoltageRegulatorSimilarityCalculator 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 VoltageRegulatorSimilarityCalculator compares voltage regulators based on:

Regulator type - Fixed (78xx/79xx) vs Adjustable (LM317/LM337)
Output voltage - Must match for fixed regulators
Polarity - Positive vs negative
Compatible families - LM317/LM338/LM350 are compatible

Applicable Types

ComponentType.VOLTAGE_REGULATOR
// Any type starting with "VOLTAGE_REGULATOR"

Returns false for null type.

Similarity Thresholds

HIGH_SIMILARITY = 0.9;   // Same voltage/compatible adjustable
MEDIUM_SIMILARITY = 0.7; // Related but different specs
LOW_SIMILARITY = 0.3;    // Different voltage or polarity

Fixed Voltage Regulators (78xx/79xx)

Positive Regulators (78xx)

| Part | Output Voltage | |------|----------------| | 7805 | +5V | | 7809 | +9V | | 7812 | +12V | | 7815 | +15V | | 7824 | +24V |

Negative Regulators (79xx)

| Part | Output Voltage | |------|----------------| | 7905 | -5V | | 7912 | -12V | | 7915 | -15V | | 7924 | -24V |

Fixed Regulator Rules

// Same voltage, different manufacturer = HIGH
calculator.calculateSimilarity("LM7805", "MC7805", registry);
// Returns 0.9

// Different voltage = LOW
calculator.calculateSimilarity("LM7805", "LM7812", registry);
// Returns 0.3

// Positive vs Negative = LOW
calculator.calculateSimilarity("LM7805", "LM7905", registry);
// Returns 0.3

Adjustable Voltage Regulators

Positive Adjustable (Compatible Family)

| Part | Current | Equivalent | |------|---------|------------| | LM317 | 1.5A | LM317T, LM317K, LM317H | | LM338 | 5A | Compatible with LM317 | | LM350 | 3A | Compatible with LM317 |

Negative Adjustable

| Part | Current | Note | |------|---------|------| | LM337 | 1.5A | Negative equivalent of LM317 |

Adjustable Regulator Rules

// Same adjustable regulator, different package = HIGH
calculator.calculateSimilarity("LM317T", "LM317K", registry);
// Returns 0.9

// Compatible positive adjustable regulators = HIGH
calculator.calculateSimilarity("LM317", "LM350", registry);
// Returns 0.9

// Positive vs Negative adjustable = LOW
calculator.calculateSimilarity("LM317", "LM337", registry);
// Returns 0.3

Package Code Handling

Common package suffixes: | Code | Package | |------|---------| | T | TO-220 | | CT | TO-220 (different pinout) | | K | TO-3 | | KC | TO-3 | | KV | TO-3 | | H | TO-39 | | S | SOT-223 | | MP | SOT-223 | | DT | TO-252 |

// Same regulator, different packages = HIGH
calculator.calculateSimilarity("LM7805CT", "LM7805T", registry);
// Returns 0.9

Manufacturer Prefixes

| Prefix | Manufacturer | |--------|--------------| | LM | National/TI | | MC | Motorola/ON Semi | | UA | Fairchild | | L78 | ST | | KA78 | Fairchild |

Test Examples

// Same voltage, different manufacturer
calculator.calculateSimilarity("LM7805", "MC7805", registry);
// Returns 0.9

// Same adjustable, different package
calculator.calculateSimilarity("LM317T", "LM317K", registry);
// Returns 0.9

// Compatible adjustable family
calculator.calculateSimilarity("LM317", "LM338", registry);
// Returns 0.9

// Different voltage
calculator.calculateSimilarity("LM7805", "LM7812", registry);
// Returns 0.3

// Positive vs negative
calculator.calculateSimilarity("LM317", "LM337", registry);
// Returns 0.3

// Non-regulator parts
calculator.calculateSimilarity("LM358", "LM324", registry);
// Returns 0.0

Learnings & Quirks

Voltage Detection

The xx in 78xx/79xx indicates voltage (05=5V, 12=12V)
Pattern: 7[89](\d{2}) extracts the voltage code

Adjustable Detection

LM317, LM337, LM338, LM350 are detected by prefix
Package suffixes (T, K, H) come after the number

Cross-Manufacturer Equivalence

LM7805 ≈ MC7805 ≈ UA7805 ≈ L7805
All major manufacturers make compatible 78xx parts

Current Rating

78Lxx = 100mA (low power)
78Mxx = 500mA (medium power)
78xx = 1A (standard)
78Hxx = 5A (high power)