21060 Corsair Blvd. Hayward, CA 94545

Vacuum Feedthroughs, Heating Elements, and Custom Thermal Systems for
Aerospace, University Research, Semiconductor, Medical and OEM Applications

Temperature Sensors


RTD and Thermcouple Assemblies

BCE Thermocouple and RTD's are offered in a wide variety of calibrations, mounting configurations, materials and sizes.

BCE RTD and Thermocouple Sensor assemblies are designed for repeatability, accuracy, and stability over the life cycle of the instrumentation. Our sensor assemblies can be specially designed for challenging applications using our applied knowledge of thermodynamics, metallurgy, and electrical properties of materials.

The Operating Principle of Thermocouples

When two dissimilar metal wires are joined together at one end, a voltage is produced at the other end that is approximately proportional to temperature. That is to say, the junction of two different metals behaves like a temperature-sensitive battery. This form of electrical temperature sensor is called a thermocouple:


This phenomenon provides us with a simple way to electrically infer temperature: simply measure the voltage produced by the junction, and you can tell the temperature of that junction. And it would be that simple, if it were not for an unavoidable consequence of electric circuits: when we connect any kind of electrical instrument to the thermocouple wires, we inevitably produce another junction of dissimilar metals. The following schematic shows this fact, where the iron-copper junction J1 is necessarily complemented by a second iron-copper junction J2 of opposing polarity:


Junction J1 is a junction of iron and copper – two dissimilar metals – which will generate a voltage related to temperature. Note that junction J2, which is necessary for the simple fact that we must somehow connect our copper-wired voltmeter to the iron wire, is also a dissimilar-metal junction which will also generate a voltage related to temperature. Further note how the polarity of junction J2 stands opposed to the polarity of junction J1 (iron = positive ; copper = negative). A third junction (J3) also exists between wires, but it is of no consequence because it is a junction of two identical metals which does not generate a temperature-dependent voltage at all.

The presence of this second voltage-generating junction (J2) helps explain why the voltmeter registers 0 volts when the entire system is at room temperature: any voltage generated by the iron-copper junctions will be equal in magnitude and opposite in polarity, resulting in a net (series-total) voltage of zero. Only when the two junctions J1 and J2 are at different temperatures will the voltmeter register any voltage at all.

Vacuum Rated Thermocouples

One of the biggest challenges facing the vacuum industry is to collect multiple readings from complex assemblies while being limited by the number of existing feedthrough ports in a vacuum chamber. With BCE’s Multi-TC, Flanged Feedthrough, companies no longer need to invest in adding more ports for a greater collection of temperatures from a vacuum environment as multiple thermocouples are embedded in just one feedthrough. The number, type and lengths of the thermocouples can be altered to match specific application requirements meeting each customers’ unique needs. As the thermocouples can be adapted to meet unique design constraints, so can this feedthrough’s flange. All sizes used are standard and are easily mountable with readily available hardware. No complicated assemblies are required for the most complicated of vacuum setups.

With most vacuum feedthroughs, troubleshooting can be difficult as well when multiple fixed elements are involved. If one element fails, generally the entire vacuum feedthrough is rendered useless. With BCE’s Multi-TC, Flanged Feedthrough, arduous troubleshooting procedures are a thing of the past. In fact, this feedthrough’s thermocouples are replaceable as they can be extracted from the compression fittings with great ease. This means that if thermocouples fail, they can be removed, tested and replaced within minutes. Thus, this no-hassle design allows for faster, more accurate and more cost-effective thermal data collection. Trust BCE’s Multi-TC, Flanged Feedthrough for your most complicated thermal detection needs.


  • Replaceable thermocouple(s) design 
  • Vacuum Integrity: 10-8 atm.cc/sec 
  • Multiple types and lengths available for thermocouple(s) 
  • Multiple types and sizes available for flange(s) 
  • Multiple types and sizes available for lead wires (KAPTON available for minimal contaminant release) 
  • Compatible O-rings available for flange(s) 
  • Can be adapted to virtually any temperature range 


Single or multipoint sensor assemblies, NIST traceable calibration on refractory thermocouple materials, 100, 1000, and 2000 Ohm RTD assemblies, stock & standard designs for quick delivery, Teflon coated probe capability.

BCE Engineering & Quality Assurance

BCE engineers provide decades of experience in design and development, delivering a wealth of empirical data and experience. BCE welcomes your custom requirement and will design and deliver a part that meets your challenging needs.

BCE is recognized for its commitment to quality and excellence by being certified in accordance with ISO 9001:2015.

ISO 9001


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