A sensor is also referred to as a transmitter or pick-up and qualitatively or quantitatively (as values) records specific (physical or chemical) properties of its environment as a technical component, whereby variables not suitable as signals are converted to signals designated for further processing.
Sensor classification based on energy usage
- Active sensor: Active sensors do not require a power source. They provide a signal in the form of an electrical voltage, charge, or current such that only changes in the measurand can be determined.
- Passive sensor: Passive sensors change an electrical parameter such as resistance, capacity, or inductivity and require a power source for this purpose. This also enables the measurement of static or quasi-static measurands and is the reason why these sensors are typically used.
- Optical sensor: Optical sensors transform non-optical variables into optical signals, which are subsequently processed further by opto-electronic devices.
Sensors (measuring elements) differ according to their measuring principle.
- Differential transformer, e. g. displacement sensor
- Inductive sensor, e. g. valve disc positioning
- Capacitive sensor, e. g. pressure or level measurement
- Bubbler control, e. g. level measurement in waste water plant
- Magnetic field measurement, e. g. distance measurement as proximity sensor
- Magneto-elastic measurement, e. g. torque or force measurement
- MIF (Magnetic-Inductive Flow measurement)
- Opto-electronic sensor, e. g. light barrier
- Piezoelectric sensor, e. g. pressure, oscillation, and force measurement
- Resistive sensor, e. g. strain gauge
- Temperature sensor, e. g. PT 100
- Thermoelectric principle, e. g. temperature measurement
- Eddy current sensor, e. g. layer thickness measurement
Configured (selected) sensors
- Absolute pressure sensor, e. g. air pressure measurement
- Differential pressure sensor
- NTC thermistor (see NTC resistor), e. g. temperature measurement
- Inductive proximity sensor, e. g. non-contact displacement/position measurement
- Inductive displacement sensor, e. g. displacement/position measurement
- PTC thermistor (see PTC resistor), e. g. temperature measurement
- Level, e. g. water, fill, sound, signal, and voltage levels
- Float switch, e. g. dry running protection for submersible motor pump
- Thermocouple, e. g. temperature measurement
If the sensors are equipped with integrated measured value conditioning, they are referred to as sensor systems.