Data Sheet

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26. Mechanical to Electrical to Mechanical
Energy
Replace the lamp (76) with the alarm (78), then turn
on the switch (62). If you turn the hand crank generator
(94 & 99), you will hear sound from the alarm (78). If
you hear no sound, then try turning the hand crank (94)
in the reverse direction. The alarm (78) makes sound
by creating vibrations in the speaker that your ear can
hear. So this circuit is an example of mechanical energy
(hand crank generator (94 & 99)) being converted
to electrical energy (current through the alarm (78))
being converted back to mechanical energy (alarm (78)
making vibrations to create sound).
27. Hand Crank Generator-controlled
Heart & Star LED
Build the circuit, turn the hand crank generator (94 &
99) and you will light up the heart LED (69) and the star
LED (70) at the same time. If the LEDs do not light, then
try reversing the direction you turn the hank crank (94).
A dynamo is a type of generator. It rotates coils
of metal wire (the mechanical energy) within
a magnetic eld to force the eld to push on
the electrons in the metal and vary its ux
(amount of eld passing through the coils).
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