American Institute of Physics
At San Francisco State University, we have developed an Automatic Millikan Device (AMI)) for measuring the charge on small drops of Mercury. The device uses a standard atomic physics laboratory Millikan chamber, a piezoelectric driven ink-jet glass dropper, and a laser-photomultiplier system for tracking the motion of the drop. This paper describes the electronic control and error detection system used with the AMO. Signals from this system are sent to a microprocessor which controls the experiment. To this date (Dec 7, 1981), we have measured 175 micrograms of Hg and found no fractional charges in 1.05 x 1020 nucleons.
Walters, W., Joyce, D. C., Abrams, P. C., Coburn, K. R., & Young, B. A. (1982). The Electronic Controls Used in a Search For Fractional Charges in Mercury Drops. Journal of Undergraduate Research in Physics, 1(2), 51–55. https://www.spsnational.org/jurp/archive/back-issues/volume-1-number-2