The sensor is a new high-tech technology used to measure physical and chemical effects. It has a wide range of applications in life.

1. Types and functions of sensors
Introduction: The sensor is a new high-tech technology used
to measure physical and chemical effects. It has a wide
range of applications in life. Sensors are divided into
many types. According to different uses and working
principles, The sensor is divided into mechanical quantity,
optical quantity, magnetic quantity, resistive type,
capacitive sensor, etc. It can be said that the sensor has
occupied many aspects of our life, and it has provided
great convenience for our life. The following is What are
the specific types of sensors and what is the role of
sensors? Let's learn together!

2. What kinds of sensors
There are the following types of sensors in life:
1. Light sensor
The photo sensor uses the semiconductor's photoconductive
effect or photovoltaic effect. The photovoltaic effect is
to detect the voltage or current generated at the
semiconductor PN junction as output by light irradiation.
Such as photosensitive diode, photosensitive tertiary and
so on. These effects take advantage of the quantum nature
of light. The most common application example is light-
controlled lamps.
2. Temperature sensor
Among the physical effects used to detect temperature, in
addition to Seebeck effect thermocouples, the resistance of
metals and oxygen semiconductors such as Pt, W, non-oxide
semiconductors, and organic semiconductors as temperature
sensors are usually used as temperature sensors. ... In
addition, there are sensors that use the current-voltage
characteristic at the PN junction to change with
temperature, the magnetic characteristics and dielectric

3. constant changes near the Curie temperature, and the
changes in dielectric constant and piezoelectric constant
to detect changes in resonance frequency. Temperature
sensor, etc. The most common application example is the
temperature control of air conditioners.
3. Pressure sensor
Most pressure sensors use some kind of piezoresistive
effect. The so-called piezoresistive effect is that when
pressure is applied to the resistor body, its resistance
value will change. This phenomenon is called the
piezoresistive phenomenon, which is much more obvious than
the change of the metal resistance. Its main reason is that
its electrons Or the mobility of holes changes. The most
common application example is the electronic scale.
4. Magnetic sensor
The commonly used effects of magnetic sensors are Hall
effect and magnetoresistive effect. The element that uses
the Hall effect is a Hall element, which is a current
flowing between the ends of a semiconductor sheet. If a
magnetic field is applied in the vertical direction of the

4. sheet, the carrier will move along the Lorentz force Moving
in a direction perpendicular to the direction of the
magnetic field, if an electrode is provided in this
direction, a voltage can be detected (Hall voltage). The
most common application example is the speed regulation
method of electric vehicles.
5. Gas sensor
The gas sensor is actually a semiconductor gas sensor.
Mainly the adsorption effect of gas. For example, a gas
sensor made by sintering semiconductor SnO2 is
polycrystalline. When gas molecules are adsorbed on the

5. surface, electron exchange occurs between the gas molecules
and the sintered body. The potential barrier at the grain
interface that controls the movement of carriers changes.
If two electrodes are provided on the sintered body, the
resistance between them will increase or decrease with the
adsorption of gas molecules. Generally, the resistance
value will decrease in reducing gas, and the resistance
value will increase in oxidizing gas. The most common
application examples are various smoke alarms.
What is the role of the sensor
What is the role of the sensor, the sensor is actually a
functional block, its role is to convert various signals
from the outside into electrical signals. The signal
detected by the sensor has increased significantly
recently, so its variety is extremely large.
In order to detect and control various signals, it is
necessary to obtain signals that are as simple and easy to
handle as possible. Only electrical signals can meet this
requirement. Electrical signals can be easily amplified,
feedback, filtered, differentiated, stored, and operated
from a distance. Therefore, a sensor as a functional block

6. can be narrowly defined as: "a type of element that
converts external input signals into electrical signals."