Charging current measurements and charging synchronization in continuous jets

The phase relationship between droplet cutoff and stimulation of a continuo us jet can be determined by pulsing the charging voltage during a time cons iderably shorter than the droplet formation period. The resulting charging current varies depending on when the pulse is applied in relation to drople t cutoff. By stepping the charging pulse over the complete droplet formatio n period the position of the droplet cutoff can be determined. The principl e of the method is discussed and a high speed ac method is proposed for per forming the measurements. The jets used in the experiments were 9.5 mum in diameter, traveling at around 53 m/s. The droplet formation frequency was a round 1 MHz. (C) 2001 American Institute of Physics.