What is the name of the sensor? Electronic sensors

The types of sensors and their names are determined by the use of various ultrasonic transducers and scanning methods in them. Depending on the type of converters, we can distinguish:

● sector mechanical sensors(sector mechanical probe) - with single-element or multi-element annular grids;

● linear sensors with multi-element linear arrays;

● convex and microconvex sensors(convex or microconvex probe) - with convex and microconvex grilles, respectively;

● phased sector sensors(phased array probe) - with multi-element linear arrays;

● sensors with two-dimensional grid th, linear, convex and sector.

Here we have named the main types of sensors, without specifying their medical purpose, operating frequency and design features.

In sector mechanical sensors (Fig. 2.11 a, 2.11 b), the working surface (protective cap) covers the volume in which there is a single-element or ring ultrasonic transducer moving along the corner. The volume under the cap is filled with an acoustically transparent liquid to reduce losses during the passage of ultrasonic signals. The main characteristic of sector mechanical sensors, in addition to the operating frequency, is the angular size of the scanning sector, which is indicated in the sensor marking (sometimes the length of the corresponding arc H is additionally given work surface). Marking example: 3.5 MHz/90°.

In linear, convex, microconvex and phased (sector) electronic scanning sensors, the working surface coincides with the emitting surface of the transducer, which is called aperture, and is equal to it in size. The characteristic sizes of apertures are used in sensor markings and help determine the choice of sensor.

In linear sensors, the aperture length L is typical (Fig. 2.11 c), since it is this that determines the width of the rectangular viewing area. Example of marking for a 7.5 MHz/42 mm linear sensor.

It should be borne in mind that the width of the viewing area in a linear sensor is always less than 20-40% of the aperture length. Thus, if the aperture size is specified as 42 mm, the width of the viewing area is no more than 34 mm.

In convex sensors, the viewing area is determined by two characteristic dimensions - the length of the arc H (sometimes its chord), corresponding to the convex working part, and the angular size of the scanning sector α in degrees Fig. 2.11 d. An example of convex sensor marking: 3.5 MHz/60°/ 60 mm. Use radius less often for marking R curvature of the working surface, for example:

3.5 MHz/60 R(radius - 60 mm).

Rice. 2.11. The main types of sensors for external inspection: a, b-

sector mechanical (a – cardiological, b – water

nozzle); c – linear electronic; g – convex;

d – microconvex; e – phased sector

In microconvex sensors, R is the characteristic radius of curvature of the working surface (aperture); sometimes an additional arc angle α is given, which determines the angular size of the viewing sector (Fig. 2.11e). Marking example: 3.5 MHz/20R (radius - 20 mm).

For a phased sector sensor, the angular size of the electronic scanning sector is given in degrees. Marking example: 3.5 MHz/90°.

Shown in Fig. 2.11 sensors are used for external inspection. In addition to them, there are a large number of intracavitary and highly specialized sensors.

It is advisable to introduce a classification of sensors according to areas of medical application.

1. Universal sensors for external inspection(abdominal probe). Universal sensors are used to examine the abdominal region and pelvic organs in adults and children.

2. Sensors for superficial organs(small parts probe). Used to study shallowly located small organs and structures (for example, the thyroid gland, peripheral vessels, joints)

3. Cardiac sensors(cardiac probe). To study the heart, sector-type sensors are used, which is due to the peculiarity of observation through the intercostal gap. Mechanical scanning sensors (single-element or with a ring array) and phased electronic sensors are used.

4. Sensors for pediatrics(podiatric probes). For pediatric patients, the same sensors are used as for adults. , but only at a higher frequency (5 or 7.5 MHz), which allows for higher image quality. This is possible due to the small size of the patients.

5. Intracavitary sensors(intracavitary probes). There is a wide variety of intracavity sensors, which differ in their areas of medical application.

● Transvaginal (intravaginal) sensors (transvaginal or edovaginal probe).

● Transrectal or endorectal probe.

● Intraoperative probes.

● Transurethral probes.

● Transesophageal probes.

● Intravascular probes.

6. Biopsy or puncture probes(biopsy or puncture probes). Used for precise guidance of biopsy or puncture needles. For this purpose, sensors are specially designed in which the needle can pass through a hole (or slot) in the working surface (aperture).

7. Highly specialized sensors. Most of the sensors mentioned above have a fairly wide range of applications. At the same time, a group of sensors with narrow applications can be distinguished, and special mention should be made of them.

● Ophthalmology probes.

● Sensors for transcranial probes.

● Sensors for diagnosing sinusitis, sinusitis and sinusitis.

● Sensors for veterinary medicine (veterinary probes).

8. Broadband and multi-frequency sensors. Broadband sensors are increasingly used in modern complex devices. These sensors are designed similarly to the conventional sensors discussed above and differ from them in that they use a broadband ultrasonic transducer, i.e. sensor with a wide operating frequency band.

9. Doppler sensors. Sensors are used only to obtain information about the speed or spectrum of blood flow speeds in the vessels. These sensors are described in the sections devoted to Doppler ultrasound devices.

10. Sensors for 3D imaging. Special sensors for obtaining 3D (three-dimensional) images are rarely used. More often, conventional two-dimensional image sensors are used together with special devices that provide scanning along the third coordinate.

The quality of the information obtained depends on the technical level of the device - the more complex and advanced the device, the higher the quality of diagnostic information. As a rule, according to the technical level, devices are divided into four groups: simple devices; middle class devices; high-end devices; high-end (sometimes called high-end) devices.

There are no agreed upon criteria for assessing the class of devices among manufacturers and users of ultrasound diagnostic equipment, since there are a very large number of characteristics and parameters by which devices can be compared with each other. Nevertheless, it is possible to evaluate the level of complexity of the equipment, on which the quality of the information obtained largely depends. One of the main technical parameters that determine the level of complexity of an ultrasonic scanner is the maximum number of receiving and transmitting channels in the electronic unit of the device, since what larger number channels, the better the sensitivity and resolution - the main characteristics of ultrasound image quality.

In simple (usually portable) ultrasonic scanners, the number of transmission and reception channels is no more than 16, in medium and high-end devices - 32, 48 and 64. In high-class devices, the number of channels can be more than 64, for example 128, 256, 512 and even more. As a rule, high-end and high-end ultrasound scanners are devices with color Doppler mapping.

High-end instruments typically take full advantage of modern digital signal processing capabilities, starting right down to the sensor output. For this reason, such devices are called digital systems or platforms.

Control questions

1. What is acoustic impedance and its effect on reflection

ultrasound?

2. How does the attenuation of ultrasound in biological tissues depend on frequency?

3. How does the spectrum of a pulsed ultrasonic signal change with depth?

4. What operating modes are provided in ultrasound scanners?

5. What is the operating mode? IN?

6. What is the operating mode? A?

7. What is the operating mode? M?

8. What is the operating mode? D?

9.Explain the operation of the ultrasonic transducer.

10. What configurations of piezoelements are found in various types

sensors?

11. What types of sensors exist in ultrasound scanners?

Electronic sensors (meters) are an important component in the automation of any technological processes and in the control of various machines and mechanisms.

Using electronic devices, you can obtain complete information about the parameters of the controlled equipment.

The operating principle of any electronic sensor is based on converting monitored indicators into a signal, which is transmitted for further processing by the control device. It is possible to measure any quantities - temperature, pressure, electrical voltage and current, light intensity and other indicators.

The popularity of electronic meters is determined by a number of design features, in particular it is possible:

• transmit measured parameters to almost any distance;
• convert indicators into digital code to achieve high sensitivity and speed;
• transfer data at the highest possible speed.

Based on their principle of operation, electronic sensors are divided into several categories. Some of the most popular are:

• capacitive;
• inductive;
• optical.

Each option has certain advantages that determine the optimal scope of its application. The operating principle of any type of meter may vary depending on the design and monitoring equipment used.

CAPACITIVE SENSORS

The operating principle of an electronic capacitive sensor is based on changing the capacitance of a flat or cylindrical capacitor depending on the movement of one of the plates. An indicator such as the dielectric constant of the medium between the plates is also taken into account. One of the advantages of such devices is their very simple design, which allows them to achieve good strength and reliability.

Also, meters of this type are not subject to distortion of indicators due to temperature changes. The only condition for accurate indicators is protection from dust, humidity and corrosion.

Capacitive sensors are widely used in a wide variety of industries. The devices are easy to manufacture, have low production costs, and at the same time have a long service life and high sensitivity.

Depending on the design, devices are divided into single-capacity and spirit-capacity. The second option is more difficult to manufacture, but is characterized by increased measurement accuracy.

Application area.

Most often, capacitive sensors are used to measure linear and angular movements, and the design of the device may vary depending on the measurement method (the area of ​​the electrodes or the gap between them changes). To measure angular displacements, sensors with a variable area of ​​capacitor plates are used.

Capacitive transducers are also used to measure pressure. The design provides for the presence of one electrode with a diaphragm, which bends under pressure, changing the capacitance of the capacitor, which is recorded by the measuring circuit.

Thus, capacitance meters can be used in any control and regulation systems. In energy, mechanical engineering, and construction, linear and angular displacement sensors are usually used. Capacitive level transmitters are most effective when working with bulk materials and liquids, and are often used in the chemical and food industries.

Electronic capacitive sensors are used to accurately measure air humidity, dielectric thickness, various strains, linear and angular accelerations, ensuring accuracy in a wide variety of conditions.

INDUCTIVE SENSORS

Non-contact inductive sensors operate on the principle of changing the inductance of a coil with a core. The key feature of meters of this type is that they only respond to changes in the location of metal objects. Metal renders direct influence to the electromagnetic field of the coil, which triggers the sensor.

Thus, using an inductive sensor, you can effectively monitor the position of metal objects in space. This allows the use of inductive meters in any industry where monitoring the position of various structural elements is required.

One of the interesting features of the sensor is that the electromagnetic field changes differently depending on the type of metal, this somewhat expands the scope of application of the devices.

Inductive sensors have a number of advantages, of which the absence of moving parts deserves special attention, which significantly increases the reliability and strength of the structure. The sensors can also be connected to industrial voltage sources, and the operating principle of the meter guarantees high sensitivity.

Inductive sensors are manufactured in several form factors for the most convenient installation and operation, for example, dual meters (two coils in one housing).

Application area.

The scope of use of inductive meters is automation in any field of industry. A simple example - the device can be used as an alternative to a limit switch, and the response speed will be increased. The sensors are housed in a dust- and moisture-proof housing for use in the most difficult conditions.

Devices can be used to measure a wide variety of quantities - for this they use converters of the measured indicator into the amount of movement, which is recorded by the device.

OPTICAL SENSORS

Non-contact electronic optical sensors are one of the most popular types of meters in industries that require effective positioning of any objects with maximum accuracy.

The operating principle of this type of meters is based on recording changes in the light flux when an object passes through it. The simplest circuit of the device is an emitter (LED) and a photodetector that converts light radiation into an electrical signal.

Modern optical meters use a modern electronic coding system that eliminates the influence of extraneous light sources (protection against false alarms).

Structurally, optical meters can be made either in separate housings for the emitter and receiver, or in one, depending on the principle of operation of the device and its field of application. The housing additionally provides protection from dust and moisture (for operation in low temperatures use special thermal casings).

Optical sensors are classified depending on their operating scheme. The most common type is barrier, consisting of an emitter and receiver located strictly opposite each other. When a constant light stream is interrupted by an object, the device generates a corresponding signal.

The second popular type is a diffuse optical meter, in which the emitter and photodetector are located in the same housing. The principle of operation is based on the reflection of a beam from an object. The reflected light flux is captured by a photodetector, after which the electronics are triggered.

The third option is a reflex optical sensor. As in a diffuse meter, the emitter and receiver are structurally made in the same housing, but the light flux is reflected from a special reflector.

Usage.

Optical sensors are widely used in automated control systems and are used to detect objects and count them. The relatively simple design ensures reliability and high measurement accuracy. Coded light signal provides protection against external factors, and electronics make it possible to determine not only the presence of objects, but also to determine their properties (dimensions, transparency, etc.).

Optical devices have become widespread in security systems, where they are used as effective motion sensors. Regardless of the type, electronic sensors are the best option For modern systems control and automatic equipment.

High accuracy and speed of measurement ensure proper functioning of the equipment with minimal deviations. Moreover, most electronic meters are non-contact, which increases the reliability of the devices several times and guarantees a long service life even in difficult production conditions.

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Electrical Engineering Encyclopedia #16.

Sensors

Inductive proximity sensor. Appearance

In industrial electronics, inductive and other sensors are used very widely.

The article will be a review (if you want, popular science). Given real instructions to sensors and links to examples.

Types of sensors

So, what exactly is a sensor? A sensor is a device that produces a specific signal when a specific event occurs. In other words, the sensor is activated under a certain condition, and an analog (proportional to the input effect) or discrete (binary, digital, i.e. two possible levels) signal appears at its output.

More precisely, we can look at Wikipedia: Sensor (sensor, from the English sensor) is a concept in control systems, a primary transducer, an element of a measuring, signaling, regulating or control device of a system that converts a controlled quantity into a signal convenient for use.

There is also a lot of other information, but I have my own, engineering-electronics-applied, vision of the issue.

There are a great variety of sensors. I will list only those types of sensors that electricians and electronics engineers have to deal with.

Inductive. Activated by the presence of metal in the trigger zone. Other names are proximity sensor, position sensor, inductive, presence sensor, inductive switch, proximity sensor or switch. The meaning is the same, and there is no need to confuse it. In English they write “proximity sensor”. In fact, this is a metal sensor.

Optical. Other names are photosensor, photoelectric sensor, optical switch. These are also used in everyday life, they are called “light sensors”

Capacitive. Triggers the presence of almost any object or substance in the field of activity.

Pressure. There is no air or oil pressure - the signal to the controller or vomits. This is if discrete. There may be a sensor with a current output, the current of which is proportional to absolute or differential pressure.

Limit switches(electrical sensor). This is a simple passive switch that trips when an object runs over or presses against it.

Sensors may also be called sensors or initiators.

That's enough for now, let's move on to the topic of the article.

The inductive sensor is discrete. The signal at its output appears when metal is present in a given zone.

The proximity sensor is based on a generator with an inductance coil. Hence the name. When metal appears in the electromagnetic field of the coil, this field changes dramatically, which affects the operation of the circuit.

Induction sensor field. The metal plate changes the resonant frequency of the oscillatory circuit

Inductive npn sensor circuit. A functional diagram is shown, which shows: a generator with an oscillating circuit, a threshold device (comparator), an NPN output transistor, protective zener diodes and diodes

Most of the pictures in the article are not mine; at the end you can download the sources.

Application of inductive sensor

Inductive proximity sensors are widely used in industrial automation to determine the position of a particular part of the mechanism. The signal from the sensor output can be input to a controller, frequency converter, relay, starter, and so on. The only condition is matching the current and voltage.

Operation of an inductive sensor. The flag moves to the right, and when it reaches the sensor's sensitivity zone, the sensor is triggered.

By the way, sensor manufacturers warn that it is not recommended to connect an incandescent light bulb directly to the sensor output. I have already written about the reasons - .

Characteristics of inductive sensors

How are the sensors different?

Almost everything that is said below applies not only to inductive, but also to optical and capacitive sensors.

Design, type of housing

There are two main options - cylindrical and rectangular. Other housings are used extremely rarely. Case material – metal (various alloys) or plastic.

Cylindrical sensor diameter

Main dimensions – 12 and 18 mm. Other diameters (4, 8, 22, 30 mm) are rarely used.

To secure an 18 mm sensor, you need 2 keys of 22 or 24 mm.

Switching distance (working gap)

This is the distance to metal plate, which guarantees reliable operation of the sensor. For miniature sensors this distance is from 0 to 2 mm, for sensors with a diameter of 12 and 18 mm - up to 4 and 8 mm, for large sensors - up to 20...30 mm.

Number of wires to connect

Let's get to the circuitry.

2-wire. The sensor is connected directly to the load circuit (for example, a starter coil). Just like we turn on the lights at home. Convenient for installation, but capricious in terms of load. They work poorly with both high and low load resistance.

2-wire sensor. Connection diagram

The load can be connected to any wire; for constant voltage it is important to maintain polarity. For sensors designed to operate with alternating voltage, neither the load connection nor the polarity matters. You don't have to think about how to connect them at all. The main thing is to provide current.

3-wire. The most common. There are two wires for power and one for load. I'll tell you more separately.

4- and 5-wire. This is possible if two load outputs are used (for example, PNP and NPN (transistor), or switching (relay). The fifth wire is the choice of operating mode or output state.

Types of sensor outputs by polarity

All discrete sensors can have only 3 types of outputs depending on the key (output) element:

Relay. Everything is clear here. The relay switches the required voltage or one of the power wires. This ensures complete galvanic isolation from the sensor power circuit, which is the main advantage of such a circuit. That is, regardless of the sensor supply voltage, you can turn on/off the load with any voltage. Mainly used in large-sized sensors.

Transistor PNP. This is a PNP sensor. The output is a PNP transistor, that is, the “positive” wire is switched. The load is constantly connected to “minus”.

Transistor NPN.At the output there is an NPN transistor, that is, the “negative” or neutral wire is switched. The load is constantly connected to the “plus”.

You can clearly understand the difference by understanding the principle of operation and switching circuits of transistors. The following rule will help: Where the emitter is connected, that wire is switched. The other wire is connected to the load permanently.

Below will be given sensor connection diagrams, which will clearly show these differences.

Types of sensors by output status (NC and NO)

Whatever the sensor, one of its main parameters is electrical state output at the moment when the sensor is not activated (no impact is made on it).

The output at this moment can be turned on (power is supplied to the load) or turned off. Accordingly, they say - a normally closed (normally closed, NC) contact or a normally open (NO) contact. In foreign equipment, respectively – NC and NO.

That is, the main thing you need to know about transistor outputs of sensors is that there can be 4 types of them, depending on the polarity of the output transistor and the initial state of the output:

• PNP NO
• PNP NC
• NPN NO
• NPN NC

Positive and negative logic of work

This concept refers rather to actuators that are connected to sensors (controllers, relays).

NEGATIVE or POSITIVE logic refers to the voltage level that activates the input.

NEGATIVE logic: the controller input is activated (logic “1”) when connected to GROUND. The S/S terminal of the controller (common wire for discrete inputs) must be connected to +24 VDC. Negative logic is used for NPN type sensors.

POSITIVE logic: the input is activated when connected to +24 VDC. The S/S controller terminal must be connected to GROUND. Use positive logic for PNP type sensors. Positive logic is used most often.

There are options for various devices and connecting sensors to them, ask in the comments and we’ll think about it together.

Continuation of the article -. In the second part, real circuits are given and the practical application of various types of sensors with transistor output is considered.

Sensors are complex devices that are often used to detect and respond to electrical or optical signals. The device converts a physical parameter (temperature, blood pressure, humidity, speed) into a signal that can be measured by the device.

The classification of sensors may be different. There are several basic parameters for the distribution of measuring devices, which will be discussed further. Basically, this separation is due to the action of various forces.

This is easy to explain using the example of temperature measurement. The mercury in a glass thermometer expands and contracts the liquid to convert a measured temperature that can be read by an observer from a calibrated glass tube.

Criterias of choice

There are certain features that must be taken into account when classifying a sensor. They are listed below:

1. Accuracy.
2. Environmental conditions - usually sensors have restrictions on temperature and humidity.
3. Range - sensor measurement limit.
4. Calibration - necessary for most measuring instruments, as readings change over time.
5. Price.
6. Repeatability - variable readings are measured repeatedly in the same environment.

Distribution by category

Sensor classifications are divided into the following categories:

1. Primary input number of parameters.
2. Principles of transduction (use of physical and chemical effects).
3. Material and technology.
4. Purpose.

The principle of transduction is the fundamental criterion followed for effective information collection. Typically, the logistical criteria are selected by the development team.

The classification of sensors based on properties is as follows:

1. Temperature: thermistors, thermocouples, resistance thermometers, microcircuits.
2. Pressure: fiber optic, vacuum, flexible liquid based pressure gauges, LVDT, electronic.
3. Flux: electromagnetic, pressure drop, positional displacement, thermal mass.
4. Level sensors: differential pressure, ultrasonic radio frequency, radar, thermal displacement.
5. Proximity and displacement: LVDT, photoelectric, capacitive, magnetic, ultrasonic.
6. Biosensors: resonant mirror, electrochemical, surface plasmon resonance, light-addressable potentiometric.
7. Image: Charge Coupled Devices, CMOS.
8. Gas and chemistry: semiconductor, infrared, conductivity, electrochemical.
9. Acceleration: gyroscopes, accelerometers.
10. Others: humidity sensor, speed sensor, mass, tilt sensor, force, viscosity.

This large group, consisting of subsections. It is noteworthy that with the discovery of new technologies, sections are constantly updated.

Purpose of sensor classification based on direction of use:

1. Control, measurement and automation of the production process.
2. Non-industrial uses: aviation, medical devices, automobiles, consumer electronics.

Sensors can be classified depending on their power requirements:

1. Active sensor - devices that require power. For example, LiDAR (light detection and ranging), photoconductive cell.
2. Passive sensor - sensors that do not require power. For example, radiometers, film photography.

These two sections include all instruments known to science.

In current applications, the purpose of sensor classification can be divided into groups as follows:

1. Accelerometers are based on microelectromechanical sensor technology. They are used to monitor patients who have pacemakers on. and vehicle dynamic systems.
2. Biosensors are based on electrochemical technology. Used for testing food, medical devices, water and detecting dangerous biological pathogens.
3. Image sensors - based on CMOS technology. They are used in consumer electronics, biometrics, traffic and security surveillance, and computer imagery.
4. Motion detectors - based on infrared, ultrasonic and microwave/radar technologies. Used in video games and simulations, light activation and security detection.

Sensor types

There is also a main group. It is divided into six main areas:

1. Temperature.
2. Infrared radiation.
3. Ultraviolet.
4. Sensor.
5. Approach, movement.
6. Ultrasound.

Each group may include subsections if the technology is even partially used as part of a specific device.

1. Temperature sensors

This is one of the main groups. The classification of temperature sensors unites all devices that have the ability to evaluate parameters based on the heating or cooling of a specific type of substance or material.

This device collects temperature information from a source and converts it into a form that other equipment or humans can understand. The best illustration of a temperature sensor is mercury in a glass thermometer. The mercury in glass expands and contracts with changes in temperature. Outside temperature is the initial element for measuring the indicator. The position of the mercury is observed by the viewer to measure the parameter. There are two main types of temperature sensors:

1. Contact sensors. This type of device requires direct physical contact with an object or carrier. They control the temperature of solids, liquids and gases over a wide temperature range.
2. Contactless sensors. This type of sensors does not require any physical contact with the measured object or medium. They control non-reflective solids and liquids, but are not useful for gases due to their natural transparency. These devices use Planck's law to measure temperature. This law concerns the heat emitted by a source to measure a benchmark.

Work with various devices

The operating principle and classification of temperature sensors are also divided into the use of technology in other types of equipment. It can be dashboards in a car and special production plants in an industrial workshop.

1. Thermocouple modules are made of two wires (each from a different homogeneous alloy or metal) that form a measuring junction by connecting at one end. This measuring unit is open to the elements being studied. The other end of the wire ends measuring device, where the reference transition is formed. Current flows through the circuit because the temperature of the two connections is different. The resulting millivolt voltage is measured to determine the temperature at the junction.
2. Resistance temperature detectors (RTDs) are types of thermistors that are manufactured to measure electrical resistance as temperature changes. They are more expensive than any other temperature detection devices.
3. Thermistors. They are another type of thermal resistor in which a large change in resistance is proportional to a small change in temperature.

2. IR sensor

This device emits or detects infrared radiation to determine a specific phase in the environment. Typically, thermal radiation is emitted by all objects in the infrared spectrum. This sensor detects a type of source that is not visible to the human eye.

The basic idea is to use infrared LEDs to transmit light waves to an object. Another IR diode of the same type must be used to detect the reflected wave from the object.

Operating principle

The classification of sensors in an automation system in this direction is common. This is due to the fact that technology makes it possible to use additional means to assess external parameters. When an infrared receiver is exposed to infrared light, a voltage difference occurs across the wires. The electrical properties of the IR sensor components can be used to measure the distance to an object. When an infrared receiver is exposed to light, a potential difference occurs across the wires.

Where it is used:

1. Thermography: According to the law of radiation of objects, one can observe the environment with or without visible light using this technology.
2. Heating: Infrared radiation can be used to cook and heat foods. They can remove ice from airplane wings. Converters are popular in industrial fields such as printing, plastic molding and polymer welding.
3. Spectroscopy: This technique is used to identify molecules by analyzing the constituent bonds. The technology uses light radiation to study organic compounds.
4. Meteorology: Measuring cloud heights and calculating ground and surface temperatures is possible if weather satellites are equipped with scanning radiometers.
5. Photobiomodulation: used for chemotherapy in cancer patients. Additionally, the technology is used to treat the herpes virus.
6. Climatology: monitoring the exchange of energy between the atmosphere and the earth.
7. Communication: An infrared laser provides light for fiber optic communication. These emissions are also used for communication on short distances between mobile and computer peripheral devices.

3. UV sensor

These sensors measure the intensity or power of the incident ultraviolet radiation. A form of electromagnetic radiation has a longer wavelength than X-rays, but is still shorter than visible radiation.

An active material known as polycrystalline diamond is used for reliable ultraviolet measurements. The instruments can detect different environmental impacts.

Device selection criteria:

1. Wavelength ranges in nanometers (nm) that can be detected by ultraviolet sensors.
2. Working temperature.
3. Accuracy.
4. Power range.

Operating principle

An ultraviolet sensor receives one type of energy signal and transmits another type of signal. To monitor and record these output flows, they are sent to an electrical meter. To create graphs and reports, the readings are transferred to an analog-to-digital converter (ADC) and then to a computer running software.

Used in the following devices:

1. Ultraviolet phototubes are radiation-sensitive sensors that monitor ultraviolet air treatment, ultraviolet water treatment and solar irradiation.
2. Light sensors - measure the intensity of the incident beam.
3. Ultraviolet sensors are charge-coupled devices (CCDs) used in laboratory imaging.
4. Ultraviolet light detectors.
5. Germicidal UV detectors.
6. Photostability sensors.

4. Touch sensor

This is another large group of devices. The classification of pressure sensors is used to assess external parameters responsible for the appearance of additional characteristics under the action of a certain object or substance.

The touch sensor acts as a variable resistor according to the location where it is connected.

The touch sensor consists of:

1. A fully conductive substance such as copper.
2. Insulated intermediate material such as foam or plastic.
3. Partially conductive material.

However, there is no strict division. The classification of pressure sensors is established by selecting a specific sensor, which evaluates the emerging voltage inside or outside the object being studied.

Operating principle

A partially conductive material resists the flow of current. The principle of a linear position sensor is that the flow of current is considered more opposite when the length of the material through which the current must pass is greater. As a result, the resistance of the material changes by changing the position in which it comes into contact with a fully conductive object.

The classification of automation sensors is based entirely on the described principle. Here additional resources are used in the form of specially developed software. Typically, the software is associated with touch sensors. Devices can remember the "last touch" when the sensor is disabled. They can register the "first touch" as soon as the sensor is activated and understand all the meanings associated with it. This action is similar to moving a computer mouse to the other end of the mouse pad to move the cursor to the far side of the screen.

5. Proximity sensor

Increasingly in modern vehicles use this technology. Classification of electrical sensors using light and touch modules is gaining popularity among automotive manufacturers.

The proximity sensor detects the presence of objects that are located with almost no contact points. Since there is no contact between the modules and the sensed object and there are no mechanical parts, these devices have a long service life and high reliability.

Different types of proximity sensors:

1. Inductive proximity sensors.
2. Capacitive proximity sensors.
3. Ultrasonic proximity sensors.
4. Photoelectric sensors.
5. Hall sensors.

Operating principle

A proximity sensor emits an electromagnetic or electrostatic field or a beam of electromagnetic radiation (such as infrared) and waits for a response signal or changes in the field. The object being detected is known as the target of the recording module.

The classification of sensors according to their operating principle and purpose will be as follows:

1. Inductive devices: There is a generator at the input that changes the loss resistance to the proximity of an electrically conductive medium. These devices are preferred for metal objects.
2. Capacitive proximity sensors: They convert the change in electrostatic capacitance between the detection electrodes and ground. This occurs when approaching a nearby object with a change in vibration frequency. To detect a nearby object, the oscillation frequency is converted into a DC voltage, which is compared with a preset threshold value. These devices are preferred for plastic objects.

The classification of measuring equipment and sensors is not limited to the description and parameters presented above. With the advent of new types of measuring instruments general group increases. Different definitions have been approved to distinguish between sensors and transducers. Sensors can be defined as an element that senses energy to produce a variant in the same or a different form of energy. The sensor converts the measured quantity into the desired output signal using the conversion principle.

Based on the received and generated signals, the principle can be divided into the following groups: electrical, mechanical, thermal, chemical, radiant and magnetic.

6. Ultrasonic sensors

An ultrasonic sensor is used to detect the presence of an object. This is achieved by emitting ultrasonic waves from the head of the device and then receiving the reflected ultrasonic signal from the corresponding object. It helps in detecting the position, presence and movement of objects.

Because ultrasonic sensors rely on sound rather than light for detection, they are widely used for water level measurements, medical scanning procedures, and in the automotive industry. Ultrasonic waves can detect invisible objects such as transparencies, glass bottles, plastic bottles and sheet glass using its reflective sensors.

Operating principle

The classification of inductive sensors is based on the scope of their use. Here it is important to take into account the physical and chemical properties of objects. The movement of ultrasonic waves varies depending on the shape and type of medium. For example, ultrasonic waves move straight through a homogeneous medium and are reflected and transmitted back to the boundary between different media. A human body in the air causes significant reflection and can be easily detected.

The technology uses the following principles:

1. Multireflection. Multiple reflection occurs when waves are reflected more than once between the sensor and the target being detected.
2. Limit zone. The minimum sensing distance and maximum sensing distance can be adjusted. This is called the limit zone.
3. Detection zone. This is the interval between the surface of the sensor head and minimum distance detection obtained by adjusting the scanning distance.

Devices equipped with this technology allow scanning of various types of objects. Ultrasonic sources are actively used in the creation of vehicles.