Working principle of accelerometer
The sensitive component converts the acceleration signal of the measuring point into the corresponding electrical signal, enters the preamplifier circuit, improves the signal-to-noise ratio of the signal through signal conditioning circuit, and then performs analog-to-digital conversion to obtain a digital signal, which is finally sent to the computer for data storage and display.
When the sensing element moves at an acceleration of a, the mass block is subjected to an inertial force opposite to the direction of acceleration, causing a deformation proportional to the acceleration of a, resulting in stress and strain on the cantilever beam. The deformation is felt by the diffusion resistance pasted on the cantilever beam. According to the piezoresistive effect of silicon, the resistance value of the diffusion resistance changes proportionally to the strain. This resistance is used as an arm of the bridge to measure the acceleration by measuring the change in the output voltage of the bridge.
When the object to be tested moves, the support and the object to be tested accelerate simultaneously. Piezoelectric components are subjected to inertial forces in the opposite direction of mass and acceleration, which generate alternating charges (voltage) on the two surfaces of the crystal. When the vibration rate is much lower than the natural frequency of the sensor, the output charge (voltage) of the sensor is proportional to the applied force 2
The principle of a linear accelerometer is the principle of inertia, which is the balance of forces. A (acceleration)=F (inertial force)/M (mass), we only need to measure F. How to measure F? Just use electromagnetic force to balance this force. We can obtain the relationship between F and current. Just use experiments to calibrate this scaling coefficient. Of course, signal transmission, amplification, and filtering in the middle are all part of the circuit.
An accelerometer naturally detects the acceleration of its own components. We won't delve into its own physical implementation. It can be imagined that there is a vacuum area inside the chip, and the sensing device is located in this area. It causes voltage changes through the action of inertial force and provides quantitative values through the internal ADC.
Detailed Photos
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