Pressure sensor 296-8060 for Caterpillar excavator part

Thermoelectric sensor

1. Thermoelectric effect

When two metal conductors A and B with different properties are connected into a closed loop, if the junction temperatures are not equal (T0≠T), an electromotive force will be generated between the two conductors, and a certain amount of current will exist in the loop. This phenomenon is called thermoelectric effect.

2. Thermal resistance sensor

Thermal resistance materials are usually pure metals, and platinum, copper, nickel, iron and so on are widely used.

3. Thermistor sensor

Thermistors are made of semiconductors and have the following characteristics compared with metal thermistors:

1) large temperature coefficient of resistance and high sensitivity;

2) simple structure, small volume and easy point measurement;

3) High resistivity and suitable for dynamic measurement;

4) The relationship between resistance and temperature change is nonlinear;

5) poor stability.

5 classified editing

There are three commonly used:

1. According to the physical quantities of sensors, they can be divided into sensors such as displacement, force, speed, temperature, flow and gas composition.

According to the working principle of sensors, they can be divided into resistance, capacitance, inductance, voltage, Hall, photoelectric, grating, thermocouple and other sensors.

2. According to the nature of the output signal of the sensor, it can be divided into: switch-type sensors whose outputs are switching values ("1" and "0" or "on" and "off"); The output is an analog sensor; Digital sensor whose output is pulse or code.

3.Sensors are used to measure the temperature and pressure of various fluids (such as intake temperature, airway pressure, cooling water temperature and fuel injection pressure, etc.); There are sensors used to determine the speed and position of each part (such as vehicle speed, throttle opening, camshaft, crankshaft, angle and speed of transmission, position of EGR, etc.); There are also sensors for measuring engine load, knock, misfire and oxygen content in exhaust gas; A sensor for determining the position of the seat; Sensors for measuring wheel speed, road height difference and tire pressure in anti-lock braking system and suspension control device; To protect the airbag of the front passenger, not only more collision sensors and acceleration sensors are needed. Facing the manufacturer's side volume, overhead airbag and more exquisite side head airbag, sensors should be added. As researchers use anti-collision sensors (ranging radar or other ranging sensors) to judge and control the lateral acceleration of the car, the instantaneous speed of each wheel and the required torque, the braking system has become an integral part of the car stability control system.