T
Type T Thermocouple
Copper / Constantan (Cu / Cu-Ni). Best stability and accuracy of all base-metal types at sub-zero and cryogenic temperatures. Per ASTM E230 / IEC 60584-1.
ASTM E230IEC 60584-1
Base MetalCryogenic ✓
At-a-Glance Specifications — ASTM E230
370°C
−200°C
9.288mV
40.6µV/°C
±1.0°C or ±0.75%
±0.5°C or ±0.4%
TX (Copper/Constantan)
ASTM E230
EMF Reference Table — Type T (ASTM E230)
| Temp (°C) | EMF (mV) | Temp (°C) | EMF (mV) | Temp (°C) | EMF (mV) |
|---|---|---|---|---|---|
| −270 | −6.258 | −50 | −1.819 | 150 | 6.704 |
| −200 | −5.603 | 0 | 0.000 | 200 | 9.288 |
| −150 | −4.648 | 50 | 2.036 | 250 | 12.013 |
| −100 | −3.379 | 100 | 4.279 | 300 | 14.862 |
| −75 | −2.788 | 125 | 5.469 | 370 | 19.027 |
Limits of Error — ASTM E230 / IEC 60584-2
| Class | Range | Limit of Error | IEC Equivalent |
|---|---|---|---|
| Standard | 0 to +370°C | ±1.0°C or ±0.75% (greater) | Class 2 |
| Special | 0 to +370°C | ±0.5°C or ±0.4% (greater) | Class 1 |
| Standard | −200 to 0°C | ±1.0°C or ±1.5% (greater) | Class 2 |
| Special | −200 to 0°C | ±0.5°C or ±0.8% (greater) | Class 1 |
Atmosphere Compatibility
✓ Oxidizing
✓ Reducing
✓ Vacuum
✓ Inert
✓ Moist H₂
✓ Cryogenic (to −270°C)
✗ Sulfurous
⚠ High temp (>370°C)
Color Code Reference
| Standard | Positive (+) | Negative (−) | Overall |
|---|---|---|---|
| ANSI (US) | Blue | Red | Blue |
| IEC 60584 | Brown | White | Brown |
Cryogenic Application Note
Type T is the preferred thermocouple for cryogenic applications because copper has predictable and stable thermoelectric properties at low temperatures, and the Constantan negative conductor maintains good sensitivity even near absolute zero. The ASTM E230 reference function extends to −270°C. For temperatures below −200°C, consult the full NIST monograph tables (ITS-90 based) rather than relying on interpolated values. Special tolerance thermocouples (±0.5°C or ±0.4%) are strongly recommended for precision cryogenic measurements.