Editing Precision Thermocouple Based Temperature Measurement System (section)

== 3. Experimental Setup==
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[[File:Schematic diagram of the experiment.png|thumb|center|700px|Schematic diagram of the experiment]]
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[[File:Experimental setup_final.jpg|thumb|500px|Experimental setup]]
[[File:Experimental setup of the sample_final_1.jpeg|thumb|500px|Experimental setup of the sample]]
[[File:Tempearture difference measurement final.jpg|thumb|200px|Temperature Difference Measurement]]
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The experimental setup comprises two copper blocks functioning as thermal reservoirs, separated by a gap of approximately 3–4 mm. Each copper block has dimensions of about 12–15 mm in width and 8–10 mm in height, providing mechanical stability while minimizing thermal mass. A ZnO slab with a thickness of  3mm and length about 6mm is positioned across the gap, overlapping slightly (~1 mm) on both blocks to ensure optimal thermal contact.
 
On the hot side, a layered structure is implemented, consisting of a copper block, a layer of Kapton tape for electrical insulation, and a power resistor serving as the heating element. The cold side features a similar configuration without the heater, allowing it to remain near ambient temperature. This arrangement establishes a controlled temperature gradient across the ZnO sample.
 
Four electrical contacts are applied to the top surface of the ZnO slab using conductive silver paste, arranged in succession from the hot side to the cold side as Tₕ, V⁺, V⁻, and T<sub>c</sub>. The total probe span is maintained at approximately 4 mm to ensure that all contact points fall within the pellet surface. Thermocouples are connected at Tₕ and T<sub>c</sub> to measure the temperature difference across the sample.
 
The Seebeck voltage is measured between the V⁺ and V⁻ contacts, while the temperature gradient is obtained from the thermocouple readings. This configuration facilitates accurate determination of the Seebeck coefficient while minimizing errors associated with contact resistance and thermal instability.

=== 3.1. Configuration of the Nano-voltmeter ===

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[[File:Image of the Nanovoltmeter.jpeg|thumb|center|700px|Configuration of the Nano-voltmeter]]
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In this experiment, the Keysight B2901A Source Measure Unit (SMU) is configured to operate as a nanovoltmeter for measuring the thermoelectric voltage generated across the ZnO pellet. The measurement is performed under near open-circuit conditions to capture the voltage arising from the Seebeck Effect, where a temperature gradient drives charge carriers and establishes an internal electric field.
To avoid perturbing this equilibrium, the SMU sources a negligible current of 0.001 nA and, with its high input impedance, minimizes loading of the sample. A two-probe configuration is used with the force terminals connected as recommended since no current flows and sense correction is not required. The trigger function initiates measurements at each new heater input, and for each ΔT, four readings are recorded and averaged. Data are stored as CSV files, and the 100 nV resolution enables detection of microvolt-level signals.