Editing Precision Thermocouple Based Temperature Measurement System (section)

== 1. Introduction ==

Temperature sensing is a fundamental requirement across a wide range of scientific and engineering applications, and the Seebeck effect offers a direct physical mechanism for transducing a thermal gradient into a measurable electrical signal. This project assembles and validates a thermoelectric sensor system comprising a sintered ZnO pellet as the active sensing element, a controlled thermal stage, and a Keysight B2901A Source Measure Unit for voltage acquisition capable of resolving the microvolt-level signals that arise from an applied temperature difference across a semiconductor material.

This study investigates the thermoelectric response of an undoped zinc oxide (ZnO) pellet through direct measurement of its Seebeck coefficient under controlled thermal gradients. The Seebeck effect refers to the generation of an electrical potential when a material is subjected to a temperature difference, and it provides a direct means of probing charge transport behaviour in semiconductors.In materials such as ZnO, the thermoelectric response is strongly influenced by intrinsic defects, grain boundaries, and carrier concentration. These features make ZnO a well-suited and instructive material for studying how microstructure affects thermoelectric transport at room temperature — a regime that remains comparatively underexplored relative to the high-temperature measurements that dominate the existing literature.

The aim of this work is to determine the Seebeck coefficient of a sintered ZnO pellet using a Keysight B2901A Source Measure Unit operated as a nanovoltmeter, under open-circuit two-probe conditions. The study further examines the linearity and reproducibility of the thermoelectric response across four independent measurement runs, with particular attention to microvolt-level signal detection, uncertainties in thermal gradient measurement, and the identification of a reliable operating window. From a sensing standpoint, this linear regime represents a stable transfer function between the applied thermal gradient and the electrical output to be a thermoelectric sensor.