Differences between Magnetoelectric And Piezoelectric Vibration Sensors

Differences between Magnetoelectric And Piezoelectric Vibration Sensors

1.Different working principles

Piezoelectric sensors measure physical quantities through the piezoelectric effect of a piezoelectric material, which generates an electric charge when it is subjected to an external force. Magnetoelectric sensors, on the other hand, use the magnetoelectric effect to measure physical quantities by using changes in the magnetic field to generate a voltage signal.

2.Different scope of application

Piezoelectric sensors have a wide range of applications and can be used to measure physical quantities such as pressure, stress, acceleration, displacement, and weight. Magnetoelectric sensors, on the other hand, are mainly used to measure physical quantities such as magnetic fields, currents, and voltages.

3.Differences in accuracy and frequency response

The measurement accuracy of piezoelectric sensors is generally higher and the error is smaller, and the accuracy can reach below 0.1%. The measurement accuracy of magnetoelectric sensors is poorer, and the general error is more than 1%.

Magnetoelectric vibration sensor response frequency range is usually tens of Hz to thousands of Hz, while the piezoelectric vibration sensor response frequency range is usually 0.1Hz to tens of thousands of Hz.

Ⅰ. Magnetoelectric sensor vibration measurement principle

Magnetoelectric sensor is a non-electrical changes can be converted into induced electromotive force of the sensor, as shown in the figure, the sensor by the permanent magnet as a moving iron, when it has a relative motion with the induction coil, the coil and the magnetic field in the magnetic flux cross-chain generates induced electromotive force. The induced electromotive force after amplification and filtering, can be used to reflect the vibration frequency and amplitude of the moving iron.

Advantages of magneto-electric vibration velocity sensors:

No external power supply is required, and the output signal can be transmitted over long distances without conditioning and amplification, which is very convenient in actual long-term monitoring.

Disadvantages of magnetoelectric vibration velocity sensors:

Due to the presence of mechanical moving parts in the magneto-electric vibration velocity sensor, it vibrates at the same frequency as the system under test, which not only restricts the upper measurement limit of the sensor, but also its fatigue limit results in a relatively short sensor life. The life of the sensor must be taken into account in long-term continuous measurements, and the life of the sensor is required to be greater than the overhaul cycle of the object to be measured.

Ⅱ.Measuring principle of piezoelectric sensors

Piezoelectric sensors are a typical type of active sensors (power generation type sensors). Piezoelectric sensing elements are force-sensitive elements that generate a charge on the surface of the dielectric under the action of an external force such as pressure, stress, acceleration, etc., thus realizing the electrical measurement of non-electrical quantities. This charge, after passing through a charge amplifier and filter, can be used to reflect changes in the external force applied to the piezoelectric sensor, as shown in the figure.

Applications for Piezoelectric Sensors

Since the charge generated by an external force on the piezoelectric element can only be retained if there is no leakage, i.e. if the measuring circuit has an infinite input impedance, which is practically impossible, piezoelectric sensors cannot be used for static measurements. Therefore, piezoelectric sensors cannot be used for static measurements. The piezoelectric element can be replenished by an alternating force and can supply a certain current to the measuring circuit, so it is only suitable for dynamic measurements (the sensitivity decreases above 50 kHz).

Sensors with high sensitivity, overload and shock resistance, good anti-interference, easy to operate, small size, light weight, reliable, high intrinsic frequency, high sensitivity and signal-to-noise ratio, widely used in medical, industrial control, transportation, security and defense and other fields.

In summary, the two sensors have their own characteristics and have different applications in different measurement scenarios, and you need to choose the right sensor according to your specific needs.

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