Measuring Principles

 

 

 

Electrochemical Sensors

Electrochemical sensors comprise of two or more electrodes between which an electrolyte is located. If the sought-after substances are detected, one of the electrodes undergoes an electrochemical (redox) reaction, resulting in the voltage difference triggering a sensor signal that can be used to determine the concentration of the substance in question.

 

Inductive Sensors

Inductive sensors make use of the fact that a magnetic field changing over time generates an electric field. If there is an electric charge, current flow occurs. In this manner, inductive sensors can be used to determine clearances or angles and, indirectly – using the local change in permeability – to test various material properties without destruction.

 

Capacitive Sensors

The capacity of a sensor depends on the distance and size of the capacitor surfaces as well as the dielectric between the surfaces. Depending on the design of the sensor, this means that changes in the clearance, the surface, or the dielectric can be used to demonstrate the presence of mechanical vibrations.

 

Optoelectronic Sensors

Optoelectronic sensors convert light of various wavelengths into an electrical signal. The light thus releases electrons from a semiconductor or metal surface, and, if there is an external electric field, the free charge carriers thus generated result in a photometric current proportional to the intensity of the light.

 

Resistive Sensors

In the case of resistive sensors, use is made of the change in ohmic resistance due to a change in position, profile, or the specific resistance of an ohmic conductor. This allows resistive sensors such as strain gauges to demonstrate deformations in mechanical devices.

 

Radar & Terahertz Sensors

Radar and terahertz sensors detect electromagnetic radiation within a wavelength range of a few millimeters to a few hundred micrometers. Active radar systems measure the runtime between emission and detection of the signal, which enables conclusions to be drawn about the speed or distance of the reflecting object.