Sensor is a device that converts non-electrical physical quantities into electrical signals. It is the "sense organ" of modern information technology. Compared with human sensory organs, it has great advantages. For this reason, it is widely used in many fields of our production and life, and plays a very important role.

1. Definition of sensor

A sensor is a device that converts non-electrical physical quantities (such as temperature, speed, humidity, height, quality, light, sound, pressure and other signals) into easily usable electrical signals (such as current, voltage, resistance, etc.) through elements sensitive to such physical quantities (such as thermistor, photosensitive resistor, force sensitive element, magnetic sensitive element, taste sensitive element, etc.). It is to convert the measured change or receive the input physical or chemical variable information into the required electrical signal output according to certain laws or requirements to meet the requirements of information transmission, display, recording, processing, storage and control. It is to convert one energy into another energy form, and the small changes of the measured signal will be converted into electrical signals. It is the "sense organ" of modern information technology, the extension of human sense, and the primary link to realize automatic detection and automatic control.

2. Types of sensors

There are many kinds of sensors with different principles and classification standards. Some are classified according to their output signals (such as analog sensors, digital sensors, etc.), some are classified according to their manufacturing processes (such as integrated sensors, thick film sensors, etc.), some are classified according to their manufacturing materials (such as metal sensors, ceramic sensors, etc.), and some are classified according to their working principles (such as resistance sensors, inductive sensors, photoelectric sensors, ultrasonic sensors, etc.). According to their uses, sensors can be roughly divided into: temperature sensor, humidity sensor, pressure sensor, photosensitive sensor, speed sensor, vibration sensor, liquid level sensor, radiation sensor, energy consumption sensor, etc.

3. Application of sensor

Sensor is a device that converts one kind of energy into another ability, and converts the measured signal into electrical signal. It has a very wide range of applications in our production, life and scientific research, ranging from military and astronomical applications to our daily life, such as cooking, washing and other automation applications. It can be said that the application of sensors has penetrated into all aspects of social life.

(1) Application of sensor in production

In the industrial automation production, with the development of modern technology, the requirements for safety production are becoming higher and higher, and the automation level of detection and control of various quantities in the production process is also becoming stronger and stronger. Sensors are widely used in steel, paper, petrochemical, pharmaceutical, food and other enterprises. For example, the application of differential pressure sensor in medicine, the application of optical fiber sensor in intelligent composite materials and thermal processing production, the application of infrared sensor in belt conveyor safety warning system, and the application of eddy current sensor in printing thickness detection. The distance sensor is used to judge the speed of vehicle movement. Humidity sensors are widely used in textile printing and dyeing production. In the production of textile printing and dyeing, due to the high requirement of humidity, it is often necessary to accurately measure the humidity of the production environment. At first, hygrometer was used to measure humidity, but with the development of modern science and technology and the complexity of humidity measurement itself, this method of measuring humidity only by hygrometer is far from competent. Humidity sensor converts water vapor in the air into electrical signal output through humidity sensor. Humidity sensor has the advantages of rapid response and accurate measurement, and is widely used in textile printing and dyeing production, improving the quality of production.

(2) Application of sensors in life

Sensors are more ubiquitous in daily life. They are changing people's lifestyle and fully show the convenience, safety and speed they bring to people's lives. For example, when we use air conditioning in summer, why does it keep the room at a set temperature? This is because there is an induction head made of thermistor in the air conditioner. When the temperature of the surrounding air changes, the resistance value of the thermistor will change accordingly, and the circuit will be converted into a current signal to control the operation of the compressor. Another example is the smoke alarm, which uses the smoke sensitive resistance to measure the concentration of smoke. When the concentration reaches a certain level, the alarm system will work, so as to achieve the purpose of alarm. In addition, our light-sensitive street lamps and sound-controlled street lamps also use sensors to automatically control the switch on and off. There are many places where sensors are used in our life, such as automatic doors, mobile phone touch screens, mice, digital cameras, electronic scales, microphones, electronic thermometers, automatic washing machines, infrared alarms, etc.