Semiconductor resistors are the most commonly used components in all electronic circuits. The resistance of a conductor to current is called conductor resistance. Semiconductor resistors, also known as sensitive resistors, are mainly made of semiconductor materials and used in the external world, such as temperature, humidity, mechanical force, voltage, magnetic field and other physical changes are sensitive to the reaction, resulting in changes in their own resistance values. Instead, one can detect changes in the above physical quantities based on changes in these resistance values. Resistance has a certain resistance value, representing the resistance to the current flow. The unit of resistance is an ohmic "Ω" specification with a symbol. The following briefly introduces the characteristics and uses of several semiconductor resistors.

 

                                                                      

 

 

 

There are many kinds of resistors that are very sensitive to temperature changes, but they can be broadly divided into two categories. First, the resistance value increases with the increase of temperature. This thermistor is called a positive temperature coefficient thermistor, also known as a positive temperature coefficient thermistor PTC element; The other is to reduce the resistance value as the temperature increases. This thermistor is called a negative temperature coefficient thermistor, also known as a negative temperature coefficient thermistor. NTC components. No matter what kind of thermistor is extremely sensitive to temperature changes: the characteristics of small thermal inertia and small size are mainly used for temperature measurement, temperature control, fire alarm, microwave and laser power measurement. For example, incubators can be found in air conditioners, refrigerators, color TV sets, microwave ovens, induction cooktops, breeding, etc.

 

 

It is a semiconductor device that is very sensitive to light. When the light increases, the resistance value decreases, and vice versa. Photoresistors are special resistors made of semiconductor materials such as cadmium sulfide or cadmium selenide. Its working principle is based on the internal photoelectric effect. The stronger the light, the lower the resistance. With the increase of light intensity, the resistance value decreases rapidly, and the bright resistance value can be as small as 1KΩ. According to the spectral characteristics of photoresistor materials, photoresistor can be divided into ultraviolet photoresistor, visible photoresistor and infrared photoresistor. Ultraviolet photoresistors are sensitive to ultraviolet light and can be used for ultraviolet detection. Visible photoresistor is mainly used in various visible photoelectric automatic control systems, such as street lights, automatic lighting beacon lights, extinguish control, electronic computer input devices, photoelectric tracking systems, etc. Infrared photoresistor is mainly used for missile guidance. Monitoring satellite attitude, astronomical exploration, gas analysis, etc. Among them, the cadmium sulfide photoresistor is very sensitive to X.α.β.gamma rays and can be used for non-destructive testing.

 

 

It is a semiconductor device that is very sensitive to voltage. When the voltage at both ends is lower than a specific value, the resistance value reaches the resistance value Mn When the voltage applied at both ends is higher than a specific value (a specific value of different specifications), the resistance value will be greatly reduced to ohms. When the applied voltage again falls below a specific value, it can automatically restore the high resistance value. According to its structure, varistors can be divided into size, junction type, single particle and film varistors. The common feature is a wide voltage range. Strong fluidity (up to thousands of amps), small voltage temperature coefficient, small size and so on. Varistors are commonly used for overvoltage protection in electronic circuits.

 

 

This is a resistance element with a magnetoresistive effect. The change in the resistance of a substance in a magnetic field is called the magnetoresistive effect. Gallium antimonide is commonly used in magnetoresistors (InSb) or indium arsenide (InAs), which are made from semiconductor materials that are magnetically sensitive. The magnetoresistive effect of semiconductor materials includes physical magnetoresistive effect and geometric magnetoresistive effect, and the physical magnetoresistive effect is also called the magnetoresistive rate effect. When the direction or strength of the increased magnetic field changes, the resistance value of the magnetoresistor will also change accordingly. Using this variation, the relative displacement of the magnetic field can be accurately measured. Measurement of magnetoresistors. Extensive use of automatic control and information processing. It can measure magnetic field strength, moving displacement, frequency, detection power and so on. In addition, it can be used for DC and AC conversion, chopping, frequency conversion and analog operations.

 

 

The use of force sensitive resistor is the use of material resistivity changes with external force phenomenon, can make mechanical force gravity, acceleration and so on into electrical signals. The force resistor can be made into torque meter, tension meter, accelerometer, pressure sensor, semiconductor microphone and so on. It is widely used in aerospace, aviation, military and civil fields.

 

 

It is the use of semiconductor surface absorption of certain gas molecules after the REDOX reaction to change the resistivity of the property. There are also many kinds of gas resistors, such as NOX, co, C02.02.S02, CXHX and so on have unique sensitivity. Gas resistor has a wide range of applications, mainly made of a variety of gas sensors, in environmental monitoring, leakage detection of various pipelines, sealing systems and safety fire prevention, explosion-proof, automatic control (such as: household range hood) and other fields can find its trace.

 

 

It is a sensitive element that uses its resistance value to change with the relative humidity of the environment and is mainly made of a wet sensing layer. The electrode is composed of an insulating substrate with a certain mechanical humidity. When the humidity layer absorbs water in the environment, the resistance value between the two electrodes decreases, directly converting the change in relative humidity into a change in resistance value. Depending on the material used in the humidors layer, there are many types of humidors. At present, humidors are mainly used in humidity detection and control systems in various fields, such as printing, pharmaceutical, papermaking: in medical research, automatic irrigation and other fields.