Sensor is a detector which can feel the measured infromation and convert it into electric signal or other infromation in desired from according to certain rules to output so as to meet the requirements of transmission, processing, storage, display, record and control of infromation. It is the primary link to realize automatic detection and automatic control.
1. Definition
It is a device which receives power from one system and usually transmits the power in another from to a second system.
2. Effect
People must resort to sensory organs in order to get infromation from the outside world. However, their function is far from enough for people to research natural phenomena and rules as well as production activities only relying on people's own sensory organs. To adapt to this situation, people need sensors. Therefore we can say, sensors are the extension of human facial features, also known as electric facial features.
The arrival of new technological revolution means that the world has begun entering the infromation age. In the process of using infromation, the first issue for us to  solve is to obtain accurate and reliable infromation and sensors are the main way and means for us to acquire the infromation in the natural and production areas.
Various sensors are used to monitor and control the parameters in the process of modern industrial production, especially automated production to enable the equipments to work in normal state or best condition and to achieve best quality products. Therefore we can say modern production would lose its foundation without numerous excellent sensors.
In basic disciplinary research, the sensor is in a more prominent position. The development of modern science and technology has involved many new areas: for example, at the macro level to observe the vast universe of thousands of light years away, at the micro level to observe microscopic particles as small as a few fms, lengthwise on the evolution of celestial bodies to observe up to hundreds of years or instant reactions within a few seconds. In addition, there have been various extreme technical studies on deepening material cognition, developing new energy resources and new materials that play an important role, such as ultra-high temperature, ultra-low temperature, ultra-high pressure, ultra-high vacuum, ultra-strong magnetic field and ultra-low magnetic field and so on. Obviously, it is impossible to obtain a lot of infromation that cannot be directly obtained by human senses without sensors. For many barriers to basic scientific research, the first is that the object infromation is difficult to obtain, while the emergence of the mechanism and new high-sensitivity detection sensors often leads to breakthrough in the field. The progress of some sensors often triggers the development some of the interdisciplinary subjects.
Sensors have already penetrated into wide areas such as industrial production, space exploitation, marine exploration, environmental protection, resource survey, medical diagnosis, biotechnology and even historic preservation. It is no exaggeration to say that nearly every modernization project from vast space to ocean as well as complex engineering systems is inseparable from a variety of sensors.
Thus it can be seen that the important role of sensor technology playing in the improvement of economy and social progress is very obvious. Various countries in the world pay great importance to the development in this field. We believe there will be a leap for sensor technology to achieve a new level corresponding to its important role in the near future.
2. Characteristics
The characteristics of sensors include: miniaturization, digitization, intelligence, multi-functionalization, systematization and networking, which not only promotes the transfromation and upgrading of traditional industries, but also establishes new industries thus becoming a new economic growth point in the 21st century. Miniaturization is based on microelectromechanical systems (MEMS) technology and has been successfully applied on silicon devices as silicon pressure sensor.