Sensors & Hardware
How Temperature Sensors Work, and the Products That Define the Category — Thermocouples, PT100, DS18B20
Every temperature sensor does the same one thing — turns heat into an electrical signal — but the physics underneath splits into four separate families: the Seebeck effect in thermocouples, the resistance-temperature relationship in RTDs and thermistors, the bandgap behavior of semiconductor ICs, and the Stefan-Boltzmann law behind infrared radiation thermometers. This piece traces the history from Seebeck's 1821 misunderstanding, through the Callendar-Van Dusen equation that calibrates PT100 sensors, to a spec comparison of real ICs like the DS18B20, TMP117, and MLX90614, and a real-world case of an F1 car reading tire temperature with 12 non-contact IR sensors.