A sensor is a device designed to detect or measure a physical input—such as temperature, pressure, light intensity, or chemical concentration—and convert that measurement into a standardized output signal. Functioning through the principle of transduction, the sensor converts a measurable ambient physical quantity into an electrical signal, which can then be processed by other electronic components. These devices are foundational to modern scientific instrumentation, automated control systems, and remote monitoring applications, enabling the continuous acquisition of data across various fields of science and engineering.