Weak Current Detection Technique for Electrostatic Droplet Ejection

Abstract

For further researching on electrostatic droplet speed camera [5][6][7]. For further researching on the electrostatic ejection, much detection methods have been studied. As the most droplet ejection and knowing more about the influence of direct and efficient approach, detection technique for weak parameters, observation and analysis of the electric signals in current (level of nA) of the jetting is present in this paper. To the ejection process are needed. As the most direct and efficient observe and analyze the signals of electric current, detection approach, detection for the weak current signals of the ejection system has been constructed. The parameters such as ejection is carried out [7]. The technique for measuring weak signals frequency, ejection consistency can be investigated. By measuring has been applied, data acquisition system was constructed to the signal waveform, we can obtain that the appearance of a peak obtain and analyze the processed current signals [8,9]. The pulse indicates a droplet ejected to the counter electrode, and in results indicate the feasibility of the detection technique. the experimental condition of this work the asymmetric frequency of jetting ranged from few tens to around one thousand hertz. According to the results, this detection technique II. PROCESS OF ELECTROSTATIC DROPLET EJECTION have proved to be feasible and valid for further researching on In this work, electrostatic droplet ejection was performed in the electrostatic droplet ejection event and knowing more about the cone-jet mode by applying a constant flow rate at constant the influence of various experimental parameters. Meanwhile, voltage [1]. That is, in the electric field caused by the voltage, this detection method has a great potential as a technical electric charge is induced on the surface of the liquid meniscus condition of intelligent control of electrostatic droplet ejection. and an electric stress stretches the meniscus in the direction of Keywords-detection technique; electrostatic droplet ejection; the field [1]. Then the electrostatic field draws the meniscus of weak current the liquid into a sharp cone called Taylor Cone [2]. When the electrostatic forces exceed the surface tension, charged liquid droplets ejected from the peak of the cone [3]. Fig. 1 shows a I.INTRODUCTION schematic representation of electrostatic droplet ejection Over the past decades, there has been much research on issuing from the stainless-steel capillary-type needle tip. electrostatic droplet ejection. The electrostatic droplet ejection technique has expected to be applied in various scopes, such as III. EXPERIMENTAL APPARATUS AND DETECTION DEVICE electronics devices, total analysis systems, combinatorial chemistry assays and bio-system devices [1][2][3][4]. ElectrostaticAs the most direct approach, detection technique for weak droplet ejection has great advantages in ejecting smaller and current of the electrostatic droplet ejection is present in this better droplets. Except that, its performance factors such as research...