Sensors

Sensor elements (or simply sensors) are electronic devices, which quantitatively or qualitatively detect physical or chemical quantities like thermal radiation, temperature, air pressure, sound, electromagnetic radiation, ph-value or acceleration and convert these quantities into electrical signals. Sensor modules and sensor systems are immediately processing the signals of the sensor elements by an electronic circuit and transfer the data to an output device or display.

Passive sensors consist of passive components like resistors, coils, capacitors, switches etc. For these sensors the corresponding electrical properties are changed by the influence of the physical quantity. These sensors usually need a power supply for operation. On the other hand active sensors convert the physical or chemical quantity to be measured into electrical energy and act as a power source. These processes are based on effects like e.g. Seebeck effect, photo effect or piezoelectrical effect.