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Les langues disponibles
Optics
Fibroptonic
Ref : 202 012
Photoresistor
ENGLISH
Transmitter
Figure 16: Set-up to determine the period of low frequency vibratory mechanical
phenomena.
2.3 Experiment:
•
Illuminate the photoresistor with a torch or better still with a laser beam.
•
Intercept the light beam with the vibrator whose period needs to be determined
(saw blade, spring, etc.)
•
Move the vibrator from its equilibrium position and observe the signal received on
the oscilloscope (figure 17)
•
The vibrator cuts the beam twice every period. Thus the period of the vibrator is
double of the signal period viewed on the oscilloscope.
•
If in the resting position, the blade of the vibrator does not cut the laser beam, the
appearance of the signal can be modified (figure 18).
Figure 17: At every half period a vibrating blade intercepts the light beam.
Receiver
Optical Fiber
Photoresistor blanked
58
Power supply 6 or 9 V =
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