Abstract :
The paper describes a portable apparatus operated from the 50-cycle a.c. mains and devised for the visual examination and/or photographic recording of controlled or uncontrolled high-speed transient phenomena. A high-vacuum glass-bulb type of cathode-ray tube is employed, with external photography. The maximum working voltage is 5000 volts, and the beam is normally shut off by means of a negative voltage on the modulating grid. A 3-electrode spark-gap is incorporated and is so arranged that when broken down by an incoming transient, or artificiallyapplied impulse, it brings the cathode-ray spot to full brilliance almost instantaneously for a controllable length of time, and, at the same time, sweeps it across the screen at a speed which can be varied from 1 or 2 microseconds to 1 millisecond for a single horizontal sweep. A simple oscillatory circuit operated by the spark-gap is arranged to provide a time-marking wave when desired.
