This paper presents a method by which a complete set of static characteristics of a power tube, including that of positive grid region, can be seen all at once on the screen of a cathode ray oscilloscope. Use is made of pulse-technique and intensity modulation of a cathode ray tube. Circuits are given and explained for observing plate characteristics on the plate current-plate voltage plane as well as constant current contours on the plate voltage-grid voltage plane, the former being shown in fig. 11 and the latter in fig 21. It is believed that the method here described will be of some help to tube manufacturers.