Elenco Upgrade Kit SC500 to SC750 - Manual (Page 18)

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Turn on the slide switch (S1); nothing
happens. Turn the switch off; the LED
(D1) flashes.
When you turn on the switch, the
electromagnet (M3) stores energy from
the batteries (B1) into a magnetic field.
When you turn off the switch, the
magnetic field collapses and the energy
from it discharges through the LED.
Modify project #529 by replacing the motor (M1) with the
antenna coil (A1). Hold down the press switch (S2) and
then watch the LED (D1) as you release the press switch.
The LED lights briefly but only after the batteries (B2) are
disconnected from the circuit.
This circuit is different from the Fan Blade Storing Energy
project because energy in the antenna coil is stored in a
magnetic field. When the press switch is released, this
field creates a brief current through the LED.
Note that the energy stored in a magnetic field acts like
mechanical momentum, unlike capacitors which store
energy as an electrical charge across a material. You can
replace the antenna with any of the capacitors but the LED
will not light. Energy stored in the magnetic fields of coils
was called electrical momentum in the early days of
electronics.
Antenna Storing
Energy
Project #529
OBJECTIVE: To show that the fan blade stores energy.
Fan Blade Storing Energy
Project #531
OBJECTIVE: To show that the antenna stores energy.
Electromagnet
Storing Energy
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 press
switch. The LED lights briefly but only after the batteries (B1) are
disconnected from the circuit.
Do you know why the LED lights? It lights because the mechanical
energy stored in the fan blade makes the motor act like a generator.
When the press switch is released, this energy creates a brief current
through the LED. If you remove the fan blade from the circuit then the
LED will never light, because the motor shaft alone does not store
enough mechanical energy.
If you reverse the motor direction, then the LED will light the same way,
but the fan may fly off after the LED lights.
This circuit was suggested by
Mike D. of Woodhaven, NY.
Project #530
OBJECTIVE: To show that the
electromagnet stores energy.
!
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over the motor.