Measuring time interval (1950 – 1970)
The advent of digital techniques in the development of counters opened up a new possibility for accurate measurements in different research areas. This concerned in particular the determination of frequency or time interval between two consecutive events. Because commercial equipment was initially unavailable and/or did not comply with military requirements, the TNO Physics Laboratory developed between 1950 and 1970 three generations of time interval meters for the Royal Netherlands Army Testing Force. These meters were used when measuring flight times and when determining the speed of projectiles.
Time interval meter with valves
This device developed in 1950 determines the time interval in units of 1 microsecond up to 1 second. The readout is made with neon lights.
Time interval meter with transistors
This model, taken into use in 1962, measures in units of 1, 10 or 100 microseconds during 1, 10 or 100 seconds respectively. The numerical display uses digivisors, that are rotational reel meters with number plate 0 to 9, one of which is projected onto a frosted glass. [see E.A.C Digivisor Mark.2]
Time interval meter with integrated circuits
This time interval meter was in use from 1970 on. Time units 0.1, 1 or 10 microseconds for 1, 10 or 100 seconds respectively. The readout was with gas discharge numeral tubes.
Photoelectric detectors have been developed for starting and stopping time interval meters. Two of these detectors detect the passing projectiles and pass the signal to a time interval meter.