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Electromagnetism
Reversible demonstration alternator
Réf :
292 075
The LED
limits the
voltage
ENGLISH
The voltage acquisition over a relative long period gives the following result:
Observation of the variable voltage with time demonstrates two important
phenomena :
1. The maximum value of the voltage decreases when the rotation speed
reduces.
2.The period (or pseudo period) increases when the rotation speed
reduces.
2.3.2. Voltage when the alternator is connected to a LED
The alternator connected to a LED is rotated by pushing on it.
The LED blinks
Observation of variable voltage with time demonstrates the behavior of the
LED:
1. The LED blinks because it only lights up during one alternation. In the
experiment made, the LED lights up during the positive alternation (if the
LED connection were inverted, it would light up during the negative
alternation). Like all diodes, the LED only allows current to pass in one
direction.
14
The LED does not blink
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