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Analog Motion Sensors
Published in Clarence W. de Silva, Sensor Systems, 2016
To overcome these problems to a great extent, a charge amplifier is commonly used as the primary signal-conditioning device for a piezoelectric sensor. The input impedance of a charge amplifier is quite high. Hence, electrical loading on the piezoelectric sensor is reduced. Furthermore, because of impedance transformation, the output impedance of a charge amplifier is rather small (very much smaller than the output impedance of a piezoelectric sensor). This virtually eliminates the loading error and provides a low-impedance output for such purposes as monitoring, signal acquisition, communication, recording, processing, and control. Also, by using a charge amplifier circuit with a relatively large time constant, the speed of charge leakage can be reduced.
Piezoelectric Sensors
Published in John Vetelino, Aravind Reghu, Introduction to Sensors, 2017
In this case a charge amplifier is placed between the coaxial line and the display device. The equivalent circuit for this sensor is shown in Figure 3.12. A charge amplifier is a circuit whose input impedance is a capacitance that provides a very high value of impedance at low frequencies. The function of the charge amplifier is to produce a voltage that is proportional to the charge on the piezoelectric plate while at the same time providing a low-output impedance. Hence, it is a charge-to-voltage converter, or what may be called an impedance converter. The charge amplifier, with its low-output impedance, essentially separates the display device from the sensing element.
Force Measurements with PZT Transducers
Published in Mesut Sahin, Howard Fidel, Raquel Perez-Castillejos, Instrumentation Handbook for Biomedical Engineers, 2020
Mesut Sahin, Howard Fidel, Raquel Perez-Castillejos
The objective of this experiment is to observe the piezoelectric effect. A charge amplifier is assembled to produce an output voltage that is proportional with the total charge generated by a PZT transducer. The output of the amplifier will be analyzed in MATLAB®. The mechanical resonance will be demonstrated using the frequency characteristics of the transducer (Figure 5.1).
Mechanical Sensing Properties of Embedded Smart Piezoelectric Sensor for Structural Health Monitoring of Concrete
Published in Research in Nondestructive Evaluation, 2021
Fei Sha, Dongyu Xu, Xin Cheng, Shifeng Huang
The output electric current of piezoelectric ceramic is weak due to its high impedance. Charge amplifier is needed to convert high-impedance charge signal into low-impedance voltage signal. Figure 1 shows the measurement circuit of piezoelectric ceramic with charge amplifier.
Influence of fuel injection pressure and injection timing on nanoparticle emission in light-duty gasoline/diesel RCCI engine
Published in Particulate Science and Technology, 2021
Mohit Raj Saxena, Rakesh Kumar Maurya
A differential pressure transmitter (Manufacturer: SENSOCON; Model: 211-D010i-2) is used for the measurement of airflow rate. The measured airflow rate at an engine speed of 1000 rpm, 1500 rpm, 1800 rpm, and 2600 rpm are 21 kg/h., 24 kg/h., 28 kg/h., and 39 kg/h, respectively. The fuel transmitter (Manufacturer: Wika; Model: SL1) is used for the measurement of fuel flow rate, while in-cylinder combustion pressure is measured using a piezoelectric pressure transducer (Manufacturer: KISTLER; Model: 603CB). This piezo-electric pressure transducer produces electric charge (in Pico-coulombs) in response to applied mechanical stress by the change in the in-cylinder pressure. A charge amplifier (Manufacturer: KISTLER Type 5018) is used for converting the electric charge into a voltage. The voltage corresponding to in-cylinder combustion pressure is logged in the computer using a high-speed data acquisition system. Crank angle position is measured by using a crank angle encoder of 0.1 CAD resolution (Manufacturer: Kubler-Germany). The “Z” signal of the encoder is used to trigger the data acquisition. The more details about the signal processing is detailed in the previous study by the authors (Saxena and Maurya 2018b). A differential mobility spectrometer (Manufacturer: Cambustion; Model: DMS500) is used for the online measurement of PSD in the size range of 5 nm to 1000 nm. The instrument consists of 38 electrometer rings (detectors) for measuring the different size particles. DMS500 is a real-time instrument, which measures the particles on the basis of their electric mobility diameter. The particle samples are collected from engine tailpipe near exhaust valve at a sampling frequency of 1 Hz. In this study, average of 60 s logged data is used for plotting PSD. The data is logged at steady-state and thermally stable condition for each operating condition. The exhaust gas sample is passed through heated sampling line (150 °C) through primary stage dilution. Diluted gases after primary dilution is transported toward the second stage dilution (high ratio diluting rotating disk) through heated line at a constant pressure of 0.25 bar. Optimal dilution ratio is chosen and controlled by a PC-based user interface, and measured particle concentration is automatically corrected for the total applied dilution. The more details about the working and measurement of particle emission is presented in the recent study by the authors (Saxena and Maurya 2020). The flame ionization detector (FID) (Manufacturer: AVL, Model: i60) is used for the measurement of total unburned hydrocarbon emissions. Combustion pressure traces of 1000 consecutive engine cycles are recorded. Averaged data of 1000 cycles are used for further calculating the combustion parameters. A few important equations used for calculating the combustion parameters are given below.