A capillary wave of the appropriate wavelength will cause a jet to break up into a stream of uniform‐sized droplets. In this paper, a theoretical expression for droplet size, radius, and spacing in terms of the jet parameters and applied frequency is derived and verified experimentally. For a given jet radius and velocity, the droplet size can be varied from its minimum value,rmin, to approximately 1.6rminby varying the driving frequency. Also, a theoretical expression for the charge on droplets resulting from the disintegration of a charged jet is shown to agree with the measured value of droplet charge.