This is an S51A model ‘Serviscope’ oscilloscope manufactured and distributed by Telequipment, a British company that specialised in such instruments. Oscilloscopes are sometimes referred to as oscillographs, and are used to calibrate and gauge the efficiency of other laboratory equipment. To do this, changes in electrical signals can be observed via the green screen on the front.
This type of equipment is based on cathode ray tube technology, which involves a vacuum tube containing one or more electron guns and a phosphorescent screen that is used to display images. This is exactly the same principle that was used in old-style television screens. The use of cathode ray technology was important for producing accurate results, and this oscilloscope contains a five-inch cathode ray tube.
Oscilloscopes were invented in 1897 by Karl Ferdinand Braun, but early versions would have looked rather different to this one. The University of Canterbury acquired this oscilloscope in the mid-1960s, and it was used in both teaching and research. Though this machine is not in use today, it is still capable of working.