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)
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