Appendix 1: Glossary of Terms: Sensors and Measurement

This glossary provides definitions for key terms used in the modules on Fundamentals of Sensors, Load Sensors and Pressure Sensing Technologies, Temperature, Flow Control, and Vision Sensors.

General Sensor Terms:

• Sensor: A device that detects and responds to a physical stimulus or change in the environment by converting it into a measurable electrical signal.
• Transducer: A broader term encompassing any device that converts one form of energy into another (e.g., sensor, microphone, speaker).
• Measurand: The physical quantity a sensor is designed to measure (e.g., temperature, pressure, distance).
• Resolution: The smallest detectable change in the physical quantity a sensor can measure.
• Accuracy: The closeness of a sensor’s measurement to the true value of the physical quantity being measured.
• Calibration: The process of adjusting a sensor to ensure its readings are accurate and consistent.
• Output Signal: The electrical signal generated by the sensor in response to the measured stimulus. This can be voltage, current, frequency, or digital data.

Load Sensor and Pressure Sensor Terms:

• Load Sensor: A sensor that measures the force or weight applied to it.
• Pressure Sensor: A sensor that measures the pressure of a gas or liquid.
• Strain Gauge: A device that converts mechanical strain (deformation) into an electrical signal. Commonly used in load sensors.
• Gauge Pressure: Pressure measured relative to atmospheric pressure (reference pressure is 0).
• Absolute Pressure: Pressure measured relative to a perfect vacuum (reference pressure is 0).
• Piezoelectric Sensor: A type of pressure sensor that utilizes the piezoelectric effect to convert pressure into a voltage signal.
• Bourdon Tube: A mechanical device used in some pressure sensors that deflects proportionally to applied pressure.
• Diaphragm Pressure Sensor: A type of pressure sensor that uses a flexible diaphragm to measure pressure.

Temperature Sensor Terms:

• Temperature Sensor: A sensor that measures temperature.
• Thermocouple: A type of temperature sensor that generates a voltage proportional to the temperature difference between its two junctions.
• RTD (Resistance Temperature Detector): A type of temperature sensor whose electrical resistance varies with temperature.
• Thermistor: A type of temperature sensor whose resistance changes significantly with temperature (more than an RTD).

Flow Sensor Terms:

• Flow Sensor: A sensor that measures the rate of flow of a fluid (liquid or gas) through a pipe or channel.
• Turbine Flow Sensor: A type of flow sensor that uses a rotating turbine blade to measure flow rate.
• Positive Displacement Flow Sensor: A type of flow sensor that measures flow rate by capturing a specific volume of fluid with each cycle.
• Mass Flow Sensor: A flow sensor that measures the mass flow rate of a fluid, taking into account both flow rate and fluid density.

Vision Sensor Terms:

• Vision Sensor: A sensor that captures and analyzes visual data (images or videos) to extract information about the environment.
• Camera: The core component of a vision sensor that captures visual data.
• Image Processing: Techniques for analyzing and manipulating digital images to extract relevant information.
• Pixel: The smallest individual element in a digital image, representing a single point of color or intensity.
• Resolution: The number of pixels in a digital image, indicating the level of detail it can capture.
• Edge Detection: An image processing technique used to identify boundaries between objects in an image.
• Thresholding: An image processing technique used to convert a grayscale image into a binary image (black and white).