Voltage Regulator Similarity Calculator Skill

Guidance for working with VoltageRegulatorSimilarityCalculator in the lib-electronic-components library.

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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

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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

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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)

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