Thermal couple is a device that measures temperature as a function of the electromotive force induced when heat is applied to two dissimilar metal wires. A variety of vacuum-side connectors are available. Thermal Couple is available from one to five TC pairs.
The wires are air-side terminated to accept one of the several connections methods: molded plug, push-on split connectors or screw connections. Vacuum-side connections might be push-on split connector, or screw mounted.
When selecting T/C feedthrough, major consideration are the temperature range, number of measurement location, and the requirement of power conductor built into the same feedthrough.
Basic Selection
| Type | TC Material | Temperature C | Compensate Wire Junction | |
| positive | Negative | |||
| T | Copper | Constantan | -184 to 400 | N/A |
| K | Chromel | Alumel | -184 to 1260 | N/A |
| J | Iron | Constantan | 0 to750 | N/A |
Type R: Noble matal (Platinum-Rhodium) thermal couple is good up to 1540 C
Type C: Refractory metal (Tungsten-Rhenium) thermal couple is good up to 2760 C