With the development of micro-electr o-mechanical system(MEMS) technolog y,the MEMS-based capacitive sensor has been widely applied in the field of ele ctron components.However,the capacitance of the micromachined sen...With the development of micro-electr o-mechanical system(MEMS) technolog y,the MEMS-based capacitive sensor has been widely applied in the field of ele ctron components.However,the capacitance of the micromachined sensor is so sma ll that the detection of the smaller value change of the capacitance is a great challenge.Based on the principle of charging and discharging of the capacitor,a kind of pulse width modulated differential circuit is introduced in this paper.For subsequent amplification,a modified amplifier is presented.The different ial circuit converts the weak capacitance change to the change of the pulse widt h of the output voltage,and the linear relationship can be obtained.And the mo dified amplifier implements the processes of amplification and filtering synchro nously,and a large DC output voltage can be obtained by the lo w-pass filter.T he designed circuits have advantages as simplified circuit,high voltage stabili ty,perfect linearity and resolution.Besides,it is feasible to be integrated w ith the sensor to largely reduce the transmission error and interference.展开更多
A new probe for atmospheric electric field mill is introduced.It consists of three parts：signal acquisition circuit for atmospheric electric field,preamplifier circuit and phase sensitive detection circuit.The signal...A new probe for atmospheric electric field mill is introduced.It consists of three parts：signal acquisition circuit for atmospheric electric field,preamplifier circuit and phase sensitive detection circuit.The signal acquisition circuit adopts the double-stator structure to form differential input circuit,thus double-precision is obtained.Preamplifier circuit is made of current-to-voltage （I-V） conversion circuit,differential amplifier circtuit and secondary amplifying circuit.The polarity of electric field is obtained via phase sensitive detection circuit.Simulation results are obtained using Multisim,and the feasibility of the designed probe is verified.展开更多
基金National High Technology Research and Development Program of China ("863"Program) (No.2011AA040404)National Natural Science Foundation of China(No.61127008)
文摘With the development of micro-electr o-mechanical system(MEMS) technolog y,the MEMS-based capacitive sensor has been widely applied in the field of ele ctron components.However,the capacitance of the micromachined sensor is so sma ll that the detection of the smaller value change of the capacitance is a great challenge.Based on the principle of charging and discharging of the capacitor,a kind of pulse width modulated differential circuit is introduced in this paper.For subsequent amplification,a modified amplifier is presented.The different ial circuit converts the weak capacitance change to the change of the pulse widt h of the output voltage,and the linear relationship can be obtained.And the mo dified amplifier implements the processes of amplification and filtering synchro nously,and a large DC output voltage can be obtained by the lo w-pass filter.T he designed circuits have advantages as simplified circuit,high voltage stabili ty,perfect linearity and resolution.Besides,it is feasible to be integrated w ith the sensor to largely reduce the transmission error and interference.
文摘A new probe for atmospheric electric field mill is introduced.It consists of three parts：signal acquisition circuit for atmospheric electric field,preamplifier circuit and phase sensitive detection circuit.The signal acquisition circuit adopts the double-stator structure to form differential input circuit,thus double-precision is obtained.Preamplifier circuit is made of current-to-voltage （I-V） conversion circuit,differential amplifier circtuit and secondary amplifying circuit.The polarity of electric field is obtained via phase sensitive detection circuit.Simulation results are obtained using Multisim,and the feasibility of the designed probe is verified.
