Low Noise Signal Conditioning Design for Electrostatic Sensors

Abstract

The signal conditioning circuit of the electrostatic sensor is a small signal amplifier that collects and amplifies the detected electrostatic noise. Due to its high amplification properties, the output signal is highly susceptible to be defaced by intrinsic or extrinsic noise. This paper is proposed a low noise signal conditioning circuit for electrostatic sensor. A circuit model is proposed as the electrode of the sensor to be used in circuit design and circuit analysis. An electrostatic noise collector amplifier is designed using a high impedance FET operational amplifier. A dual power supply using a single battery is provided to isolate the circuit from 50 Hz extrinsic noise. The design is investigated for its gain, bandwidth and noise properties. The sensor test results verified the design objectives. The circuit can be used to design a low noise measurement system using an electrostatic sensor in powder and particle technologies.

Keywords

• Electrostatic sensor
• Metal electrode
• Circuit model
• Signal collector
• Extrinsic noise
• Frequency spectrum.