What is sensor?
A sensor is an electronic device capable of sensing physical or chemical changes in a survey environment. Sensors will convert the received signals into electrical signals to collect information about the state of that process.
These information will be collected and processed to provide qualitative or quantitative parameters of the environment. Sensors are used in machinery and equipment for measurement, scientific and technical research in many different fields.
The quantity information to be measured such as temperature, pressure, distance… that affects the sensor will give a characteristic quantity of electrical properties such as charge, voltage or current. Sensors are usually arranged in positions such as transducers and receivers combined with electrical circuits.
General structure of the sensor
The sensor construction includes circuit element sensors to form a complete system circuitry in a compact package. When the output signals will be normalized according to the voltage and current levels according to the controller. The sensor has a transducer that picks up a signal that changes according to the variation of that environment.
Classification of sensors
On the market today, there are many different sensors according to their structure, operating principle or properties… There are many ways to classify sensors, you can refer to the types of sensors as well as the types of sensors right below.
Active and passive sensors
+ Active sensors are sensors that use electricity to convert electrical signals. These sensors are made from ceramic materials that convert pressure into an electrical charge on the surface. Currently, antennas are all active sensors.
+ Passive sensors are simply understood as sensors that do not use additional power to be able to convert to an electrical signal. Photodiodes that operate when illuminated by light will change the level of the reverse biased p-n semiconductor junction resistance. These types of rheostats are also passive sensors.
Classification of sensors according to the principle of operation
+ Resistance sensor: is a type of sensor that works on the principle of moving the runner (or the rotation angle of the rheostat), or the change in resistance due to the expansion of the conductor.
+ Touch sensor
+ Capacitive sensor: is a type of capacitance conversion when the distance between the metal object and the sensor changes.
+ Electric field sensor (abbreviated FET): works based on changing electric field to change the amperage inside the sensor.
+ Magnetic field sensors include Hall effect sensors, magnetic field sensors with ferromagnetic materials…
+ Piezoelectric sensor: has the function of converting pressure to electricity using piezoelectric ceramics such as barium titanate, recording mic, seismic wave receiver…
+ Optical sensors: are image sensors of the CMOS or CCD type used in cameras, paper detectors of printers, etc.
+ Temperature sensor: widely used in temperature probes, bimetallic pairs, semiconductor components…
Classification of touch by properties
+ Temperature Sensors: Types of temperature sensors are known by other names such as thermocouple, thermistor, temperature sensor, temperature sensor, temperature wire, etc., which use sensors to measure temperature. When the temperature shows signs of change, the sensor will measure and give a signal so that the reader will conduct analysis and provide the measurement result as the temperature.
+ Optical Sensors: Optical sensor is understood as a type of sensor with the function of detecting objects, measuring distances, measuring the moving speed of objects to be measured, … based on the principle of light. When light hits the surface of optical sensors, they can change their properties.
+ Pressure Sensors: This type of sensor has the main function of measuring pressure and pressure in objects such as tanks, gas and steam pipelines.. The sensor helps to control the pressure or pressure of the object.
Pressure sensors also have many different types such as differential pressure sensors, relative sensors, negative pressure sensors, absolute pressure sensors…
Applications of sensors in Automation
For the development of industry, especially the modernization in production. Sensors play an important role in the automation system as well as being able to control the production process of factories.
Applications of sensors in industry are as follows:
+ Identify and sense input and output control signals
+ Measure the values.
+ Feel the quantity with the physics to be measured.
+Production line control, product filtering, product counting…
