Why does the pressure sensor make noise

No matter how carefully we maintain the pressure sensor in daily use, there may be a problem in use, that is noise problem. The low frequency noise of pressure sensor is mainly caused by the discontinuity of conductive particles inside, especially for the carbon film resistance, there are many tiny particles inside the carbon material, and the particles are discontinuous. When the current flow expires, the conductivity of the resistance will change, resulting in the change of current, resulting in a flash arc similar to poor contact.

For the bulk noise produced by semiconductor devices, it is mainly due to the change of the number of charges accumulated in this area caused by the change of the voltage in the barrier area at both ends of the semiconductor pn junction, which shows the capacitance effect. When the forward voltage is reduced, the electrons and holes are separated from the depletion region, which is equivalent to the capacitance discharge. When the reverse voltage is applied, the variation of depletion region is opposite. When the current flows through the barrier area, this change will cause a small fluctuation of the current flowing through the barrier area, resulting in current noise. In general, the electromagnetic components on the circuit board of pressure sensor, if there is interference on many circuit boards, there are relay, coil and other electromagnetic components. The inductance of the coil and the distributed capacitance of the shell radiate energy to the vicinity when the electricity is smooth and out of date, and the energy will produce interference on the nearby circuit. As the relay and other components work repeatedly, the instantaneous reverse high voltage will be generated when the power is turned on and off, forming the instantaneous surge current. This instantaneous high voltage will have a great impact on the circuit, thus seriously interfering with the normal operation of the circuit.