A new optically sensed thermal element for precise AC-DC conversion

An optically sensed isothermal differential thermal converter has been reduced to practice using a commercially available optical infrared pyrometer. Eliminating the conventional bimetallic thermocouples avoids draining thermal energy from the heater, reduces the Thomson effect error, and minimizes shunt paths along the heater which bypass higher frequency signal components. The optically sensed thermal element provides the potential for greater accuracy over a wide frequency range, faster response time, and improved dynamic range over conventional wire or planar thermal elements using Seebeck, thermoresistive or semiconductor temperature sensing