Fuel pressure sensor 3083716 for Dongfeng motor excavator

Pressure sensor is a device with pressure sensitive elements, which measures the pressure of gas or liquid through a diaphragm made of stainless steel and silicon. When using the pressure sensor, some problems will inevitably appear, such as noise. What is the cause of the noise? This may be due to the discontinuity of internal conductive particles, or shot noise generated by semiconductor devices. Other reasons will be described in detail below.

Causes of noise in pressure sensor

1. The low-frequency noise of pressure sensor is mainly caused by the discontinuity of internal conductive particles. Especially for carbon film resistance, there are often many tiny particles in carbon materials, and the particles are discontinuous. In the process of current flow, the conductivity of the resistor will change, and the current will also change, resulting in a flash arc similar to poor contact.

2. The scattered particle noise produced by semiconductor devices is mainly due to the change of the voltage at the barrier region at both ends of the semiconductor PN junction, which leads to the change of the accumulated charge in this region, thus showing the influence of capacitance. When the direct voltage decreases, the depletion region of electrons and holes widens, which is equivalent to capacitor discharge.

3. When the reverse voltage is applied, the depletion region changes in the opposite direction. When the current flows through the barrier region, this change will cause the current flowing through the barrier region to fluctuate slightly, thus generating current noise. Generally, in the electromagnetic components on the pressure sensor circuit board, if there is interference, many circuit boards have electromagnetic components such as relays and coils. In the process of steady current flow, the inductance of the coil and the distributed capacitance of the shell radiate energy to the vicinity. Energy will interfere with nearby circuits.

4. Work repeatedly like relays and other components. Power-on and power-off will produce instantaneous reverse high voltage and instantaneous surge current. This instantaneous high voltage will have a great impact on the circuit, which will seriously interfere with the normal work of the power supply. Circuit.