5V
1A
or
!
WARNING:
Moving parts. Do not
touch the fan or motor during operation.
!
WARNING:
Do not lean over the motor.
Project 59
Generator
SET THE SWITCHER (S6) TO THE MIDDLE POSITION BEFORE COMPLET-
ING THE CIRCUIT. Build the circuit as shown, leave the fan off the motor (M1).
Set the meter (M5) to the 5V scale for now.
Set the switcher to the right position to get the motor spinning, then set it to the
left position and watch the meter to see how much voltage is produced.
Next, set the meter to the 1A scale and set the switcher to the right for a few
seconds, then set it to the left and watch the current produced.
Part B:
Put the fan on the motor and repeat the above tests to see what volt-
age and current are produced with the fan on the motor.
+
This circuit uses the batteries (B3) to get the motor spinning, then disconnects
the batteries and uses the motor as a generator. A
generator
uses mechan-
ical motion (here the spinning motor shaft) to create electricity (a current in a
coil in the motor). The meter shows how much current and voltage are pro-
duced by the spinning shaft, with and without the fan.
Compare the electrical energy produced by the generator (the motor): Is the
voltage higher with or without the fan?
Is the current higher with or without the fan?
Does the voltage/current last longer with or without the fan?
Add the white LED (D6) to the preceding circuit, as shown.
Set the switcher to the right to get the motor spinning, then
set it to the left and watch the white LED. Do it both with and
without the fan on the motor, comparing the light from the
LED.
Project 60
Generator with Light
If you replace the white LED with the lamp (L4), how bright
will the lamp get? (Try it, both with and without the fan.)
5V
1A
or
The white LED needs about 3V to turn
on, so should get bright without the
fan, but may not light at all with the fan.
The lamp needs a sustained high cur-
rent to heat up its filament enough to
produce light.
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