Active sensors are also referred to as parametric sensors. These are sensors that must be powered by an external source. GPS and radar sensors are examples of active sensors.
Passive sensors are also known as self-generated sensors. It produces its own electrical signal and does not require an external power source. Examples of passive sensors include thermal sensors, electric field sensing, and metal detecting.
Contact sensors require physical contact with their stimulus. Temperature and strain gauge sensors are common examples of contact sensors.
Non-Contact Sensors, on the other hand, do not need to be physically touched. Optical and magnetic sensors, as well as infrared thermometers, are examples of these types of sensors.
Absolute Sensors live up to their name by providing a precise reading of their stimulus. A thermistor, for example, always measures the exact, or absolute, temperature reading.
Relative Sensors are used to measure a fixed or variable measurement. A thermocouple is an example of a relative sensor because it measures the temperature difference rather than the actual temperature.
Analog sensors generate continuous analog output signals that are proportional to their measurement. Accelerometers, pressure sensors, light sensors, and sound sensors are some examples of analog sensors.
Digital sensors (also known as electronic or electrochemical sensors) digitally convert data transmission. Digital accelerometers, pressure sensors, and temperature sensors are a few examples.
Scalar sensor: detects the input parameter solely on its magnitude. The sensor's response is a function of the magnitude of some input parameter. The direction of the input parameters has no effect. Temperature, gas, strain, color, and smoke sensors are some examples.
Vector sensor: The sensor's response is determined by the magnitude of the direction and orientation of the input parameter. Sensors such as accelerometers, gyroscopes, magnetic fields, and motion detectors are some examples.