The charge amplifier is an important building block in various electronic circuits. In this paper a new charge amplifier for piezoelectric sensors is introduced. The advantages of the new proposed charge amplifier becomes obvious in the quasi-static applications. In some quasi-static applications the traditional charge amplifiers uses an extremely large feedback resistor (in the range of $\text{G}\Omega $ ) whereas the proposed charge amplifier no longer requires such extremely large resistors. Moreover the proposed circuit reduces the output offset voltage significantly in comparison with conventional charge amplifier. The proposed circuit can be also implemented by using general purpose JFET operational amplifiers instead of using electrometer operational amplifiers therefore the cost of implementation will be reduced significantly in comparison with conventional charge amplifier. The proposed charge amplifier was assembled by using general purpose JFET Op-Amp to capture and amplify the output voltage of the piezoelectric vibration sensor Minisense100. In this experiment the low-cutoff frequency and the gain of the proposed charge amplifier were set equal to 0.2Hz and 20.5 dB respectively. The output offset voltage of the circuit was measured equal to 210 $\mu \text{V}$ .The measurement of very small vibration (±0.015g) showed a relative error equal to 2.1% with respect to the value which is obtained by using vibration meter as reference.

中文翻译：

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一种用于压电传感器的新型低输出失调电压电荷放大器

电荷放大器是各种电子电路中的重要组成部分。本文介绍了一种用于压电传感器的新型电荷放大器。新提出的电荷放大器的优势在准静态应用中变得明显。在一些准静态应用中，传统的电荷放大器使用了一个非常大的反馈电阻（在 $\text{G}\Omega $ 范围内），而建议的电荷放大器不再需要这么大的电阻。此外，与传统的电荷放大器相比，所提出的电路显着降低了输出偏移电压。所提出的电路也可以通过使用通用 JFET 运算放大器而不是使用静电计运算放大器来实现，因此与传统电荷放大器相比，实现成本将显着降低。建议的电荷放大器是通过使用通用 JFET 运算放大器来组装的，以捕获和放大压电振动​​传感器 Minisense100 的输出电压。在这个实验中，所提出的电荷放大器的低截止频率和增益分别设置为 0.2Hz 和 20.5dB。测量电路的输出偏移电压等于 210 $\mu \text{V}$ 。非常小的振动 (±0.015g) 的测量显示相对误差等于 2.1%，相对于由以下获得的值以振动计为参考。