Overview
BT137 and BTA08 are both bidirectional TRIACs, but they differ in parameters, packaging and application scenarios.Here’s a comparison:
Parameters Comparison
| Parameter | BT137 | BTA08 |
|---|---|---|
| Current Rating | 8A (RMS) | 8A (RMS) |
| Voltage Rating | 600V/800V (e.g., BT137-600) | 600V/800V (e.g., BTA08-600) |
| Trigger Current | ~5mA (typical) | ~10–50mA (less sensitive) |
| Package | TO-220C (non-insulated, requires isolation) | TO-220AB(fully insulated) |
| On-State Voltage Drop | ~1.6V (typical) | ~1.5V (typical) |
Key Differences
- Package & Isolation
BT137: TO-220C package,requires an insulating pad when mounted on a heatsink.
BTA08: TO-220A package,available in insulated packages,no extra insulation is needed for heatsink mounting. - Trigger Sensitivity
BT137: Lower gate trigger current (~5mA), making it easier to drive directly from low-power circuits.
BTA08: Higher trigger current (typically 10–50mA), requiring a stronger gate drive. - Heat Dissipation
BT137: Requires an insulating pad, which can slightly reduce thermal efficiency.
BTA08 (insulated models): No insulation needed, but plastic packaging may limit heat dissipation compared to metal tabs. - Typical Applications
BT137: Used in low-power AC control (e.g., dimmers, small motor controls, household appliances).
BTA08: Preferred for industrial applications (e.g., heaters, high-power switching) due to its ruggedness and insulated options.
Interchangeability
If voltage/current ratings match (e.g., 600V/8A), they can be substituted, but consider:
- Replacing BT137 with BTA08: Ensure the gate drive circuit can supply enough trigger current.
- Replacing BTA08 with BT137: Add an insulating pad if the heatsink is grounded.
Selection Guide
- Choose BT137 for cost-sensitive, low-power designs with simple triggering.
- Choose BTA08 for industrial or safety-critical applications where insulation is required.
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