What is a sensor?

Watch the video

What is a sensor?

Surely you have heard this many timesword, as a "sensor". Obviously, this word means some kind of technical device. What is the sensor and how does it work? What kinds of sensors are there? Let's consider all these questions in more detail.

The concept of a sensor

At the present time it is customary to call a sensoran element that converts the information received from the medium into an electrical signal in order to further transfer information to some other device. Usually the sensor is a structurally isolated part of the measuring system.

Sensors are used everywhere: in cars, heating systems, water supply, in the workplace, in medicine, even in catering establishments for measuring temperature in order to determine the degree of readiness of the dish.

Classification of sensors

There are several types of sensor classification. We give the most basic.

By type of measurement:

Pressure Sensors;
Flow sensors;
Level measurement sensors;
Temperature sensors;
Concentration sensors;
Radioactivity sensors;
Motion sensors;
Angular position sensors;
Sensors for measuring mechanical quantities;
Vibration sensors.

Classification by manufacturing technology:

Element sensors;
Sensors integrated.

Classification by the principle of action:

These include:

Optical sensors that useelectromagnetic radiation and react to water vapor, smoke and various types of aerosols. Relate to non-contact sensors. At the heart of the principle of their work is the capture of a sensitive sensor by the influence of some stimulus, for example, water vapor. These sensors are widely used in automated control systems.
Inductive sensors. Relate to non-contact sensors, designed to perform the calculation of the position of the object. Inductive sensors perfectly capture the fluctuations of the electromagnetic field. At the heart of their design is the generator, which creates an electromagnetic field, the effect of which on the metal object generates the amplitude of the oscillations, to which the sensor responds. Such sensors are widely used in metal detectors, as well as in various kinds of electronic locks.
Capacitive sensors. These sensors are used in cars as rain sensors, touch buttons for home appliances, liquid sensors. The principle of their action is to react to the effects of liquid. The insulator of such sensors has a dielectric constant. The fluid, acting on the insulator, causes the appearance of an electrical signal that is converted into information. Such sensors are widely used in household appliances.
Strain gauges. Strain gauges are a device for measuring force, pressure, torque, acceleration or displacement. The mechanism of their action is based on the principle of elasticity. Such sensors are widely used in various types of scales. They convert the amount of deformation into an electrical signal, in other words, the sensor catches the effect of some force on it, after which the elastic element is deformed and a resistance of the strain gage, which is built into such a sensor, occurs. Then the information is converted into an electrical signal and transferred to another device, for example, a display.
Piezoelectric sensors. Such sensors are widely used in microphones and sonars. Their principle of operation is based on the polarization of the dielectric under the influence of mechanical stresses. In other words, piezoelectric sensors detect the change in the electric field to which a mechanical effect was applied. For example, in a microphone this is the impact of a voice. The result of deformation is the conversion of the received signal into an electrical signal and transferring it to another device. These sensors were born thanks to Jacques and Pierre Curie in the 1880s.
Magnetic-electric sensors. These are sensors whose operation principle is based on the so-called Hall effect. These sensors are used in smartphones as the basis for the operation of the electronic compass, in electric motors, in current meters.
Nano-sensors. Are under development. The most demanded area for them should be medicine and robotics. It is assumed that these sensors will become a new class and will find widespread use in the future. Their operating principle will be similar to many other sensors (hence the names of nano-piezoelectric sensors, nano-strain gauges, etc.), but their dimensions will be many times smaller

In order to learn more about the sensors, read these articles: