Stopwatch and Timer Calibrations - National Institute of Standards ...

List of Figures
List of Figures
Figure 1. The calibration and traceability hierarchy..................................6
Figure 2. Type I digital stopwatch.............................................................11
Figure 3. Type II mechanical stopwatch....................................................11
Figure 4. Interior of digital (Type I) stopwatch.........................................12
Figure 5. Inner workings of a mechanical (Type II) stopwatch or timer...13
Figure 6. A collection of timers................................................................14
Figure 7. Sample manufacturer’s specifications for a digital stopwatch
(Example 1)...............................................................................18
Figure 8. Sample specifications for a digital stopwatch (Example 2)......20
Figure 9. Typical performance of quartz wristwatches using 32 768
Hz time base oscillators............................................................21
Figure 10. Portable shortwave radio receiver for reception of audio
time signals..............................................................................30
Figure 11. Reaction time measurements (four operators, 10 runs each)
for the direct comparison method.............................................36
Figure 12. Averaging measurement results for four different operators....36
Figure 13. Block diagram of the totalize method.....................................41
Figure 14. Using the start-stop button of the stopwatch to start the
counter......................................................................................42
Figure 15. Measured reaction times (four operators, 10 runs each) for
totalize method.........................................................................44
Figure 16. Mean reaction times (four operators, 10 runs each) for the
totalize method.........................................................................45
Figure 17. Photo totalize start reading......................................................47
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