What is a sensor
Sensor is a detection device, can feel the measured information, and can feel the information, according to certain laws transformed into electrical signals or other required forms of information output to meet the requirements of information transmission, processing, storage, display, recording and control.
The characteristics of the sensor include: miniaturization, digitalization, intelligence, multi-functionalization, systematization, networking. It is the primary link to achieve automatic detection and automatic control. The existence and development of sensors gives objects senses such as touch, taste and smell, making them slowly come to life. They are usually divided into ten categories based on their basic sensory functions: thermal elements, photosensitive elements, gas-sensitive elements, force-sensitive elements, magnetic elements, moisture-sensitive elements, sound-sensitive elements, radiation-sensitive elements, color-sensitive elements, and taste-sensitive elements.
Composition of sensors
Sensors are generally composed of four parts: sensitive elements, conversion elements, transformation circuits and auxiliary power supplies.
Sensitive elements directly feel the measured, and output a physical quantity signal with the measured relationship; conversion elements will be sensitive to the physical quantity signal output into an electrical signal; conversion circuit is responsible for the conversion of the electrical signal output from the conversion element to amplify the modulation; conversion elements and conversion circuit generally also requires an auxiliary power supply.
6 Types of sensors
- Resistive type
Resistive sensor is a device that converts physical quantities such as displacement, deformation, force, acceleration, humidity, temperature, etc., into resistive values. There are mainly resistive strain gauge, piezoresistive, RTD, thermal, gas sensitive, moisture sensitive and other resistive sensor devices.
- Frequency conversion power
Inverter power sensor through the input voltage, current signal for AC sampling, and then the sampling value through the cable, optical fiber and other transmission systems connected to the digital input secondary instrument, digital input secondary instrument for voltage, current sampling value of the operation, you can get the voltage rms value, current rms value, fundamental voltage, fundamental current, harmonic voltage, harmonic current, active power, fundamental power, harmonic Power and other parameters.
- Weighing
Load cell is a force→electric conversion device capable of converting gravity into electrical signals
The composition of the sensor _ sensor principle and application
- RTD
RTD temperature measurement is based on the property that the resistance of a metal conductor increases with temperature to measure temperature. Most RTDs are made of pure metal. There are positive temperature coefficient sensors and negative temperature coefficient sensors.
- Laser
A sensor that uses laser technology for measurement. It consists of a laser, a laser detector and a measurement circuit. Laser sensor is a new type of measurement instrument.
6. Hall
Hall sensor is a magnetic field sensor made according to the Hall effect. Hall sensors are divided into two types: linear Hall sensors and switching Hall sensors. Linear Hall sensor consists of Hall element, linear amplifier and emitter follower, which outputs analog quantity. And the switching type Hall sensor consists of voltage regulator, Hall element, differential amplifier, Smitter trigger and output stage, which outputs digital quantity.
The principle of some sensor applications
- Resistive: mechanical deformation of the metal conductor by the action of external forces blind, its resistance value changes with the change in mechanical deformation
- Hall: Hall effect: metal or semiconductor sheet placed in a magnetic field, when there is a current through, in the direction perpendicular to the current and the magnetic field will produce an electric potential.
