HIGH-FREQUENCY OSCILLOGRAPHY WITH ELECTROSTATICALLY DEFLECTED INK JETS

Abstract : A method is given of forming, charging, and electrostatically deflecting a high-speed jet of small, fluid droplets, and the application of this technique to a high-frequency oscillograph. Constructed were experimental oscillographs that produce traces with amplitudes up to 2 cm peak-to-peak; this 2-cm span may be traversed in as little as 10 microseconds. The amplitude accuracy of the record is typically =5% and is limited by spurious deflections of the ink droplets during flight caused by aerodynamic drag and mutual electrostatic repulsion between adjacent charged droplets. A flow of air is established in the space traversed by the ink droplets. An analysis of distortion phenomena indicates that fidelity decreases as parameters of the system are changed to give higher maximum trace amplitude or higher drop- formation frequency.