Flexible Type-T Thermocouple Design & Assembly

This was a unique and technically challenging project for us at Elcoan Lanka. Our USA-based client approached us with the requirement to redesign an environmental monitoring probe into a flexible, low-mass, Type-T thermocouple assembly with an integrated 10 kΩ NTC thermistor for cold-junction temperature sensing.

The main goals were to create working prototypes on a polyimide flexible substrate, while ensuring fast thermal response, reliable electrical performance, and robust mechanical design suitable for repeated environmental use.

Key Challenges

• Maintaining uniform junction geometry across all channels for consistent performance
• Achieving a true Type-T thermocouple junction (Copper–Constantan) directly on a flexible PCB without contamination from plating
• Minimizing thermal mass at each junction point for a faster and more accurate response
• Adding mechanical strain relief to withstand continuous bending and handling

What We Offered

We carefully studied the client's specifications and existing probe design to understand the exact performance requirements. From there, we developed a complete redesign from schematic to prototype tailored for the polyimide flexible substrate.

Our Work Included

• Full schematic and flexible PCB layout design
• Material selection optimized for thermal accuracy and durability
• Prototype fabrication and iterative testing
• Cold-junction compensation circuit integration with 10 kΩ NTC thermistor
• Strain relief design for repeated bending cycles

The result was a lightweight, high-accuracy thermocouple assembly ready for environmental monitoring applications delivered on time and meeting all client specifications.