Elenco Circuit Maker Skill Builder 125 - Manual (Page 48)

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Project #92 Fan Flash Energy
Project #93
Photo Timer Light
Project #94
Room Light to Red Light
Place the fan on the motor (M1). Hold down the press switch (S2) for
a few seconds and then watch the LED (D1) as you release the switch.
The LED flashes briefly but only after the batteries (B1) are
disconnected from the circuit.
Do you know why the LED flashes? It flashes because the mechanical
energy stored in the fan blade makes the motor act like a generator.
When the switch is released, this energy creates a brief current
through the LED.
If you reverse the motor direction, then the LED will light the same way,
but the fan may fly off after the LED lights.
Press and release the
press switch (S2), then
turn on the slide switch
(S1). The LED will light
for a while when there
is room light on the
photoresistor (RP) and
slowly dims.
The capacitor (C5) will
store energy until a light
shines on the photo
resistor to release the
energy, which activates
the NPN transistor (Q2)
and turns on the LED
(D1). Press the press
switch again to
recharge the capacitor.
!
WARNING: Moving parts. Do not
touch the fan or motor during operation.
!
WARNING: Do not
lean over the motor.
Turn on the switch, the
brightness of the LED
depends on how much room
light shines on the
photoresistor. The resistance
drops as more light shines,
allowing more current to the
NPN.
CM-125_Manual_031514.qxp_CM-125_Manual_031514 4/2/14 12:20 PM Page 48