Elenco Upgrade Kit SC500 to SC750 - Manual (Page 16)

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SCR’s are often used to control the speed of a motor. The voltage to
the gate would be a stream of pulses, and the pulses are made wider
to increase the motor speed.
Place the fan on the motor (M1) and turn on the slide switch (S1). The
motor spins and the lamp (L2) lights. Wave your hand over the
photoresistor (RP) to control how much light shines on it, this will
adjust the speed of the motor. By moving your hand in a repetitive
motion, you should be able spin the motor at a slow and steady speed.
Project #525
OBJECTIVE: To show how an SCR is used.
SCR Motor Control
Project #526
OBJECTIVE: To show the different types of output from Snap
Circuits
® .
Output Forms
Set the meter (M2) to the LOW (or 10mA) scale. This circuit uses all
six forms of output available in Snap Circuits
® - speaker (SP, sound),
lamp (L1, light), LED (D1, light), motor (M1, motion), 7-segment
display (D7, light), and meter (M2, motion of pointer).
Place the fan on the motor, turn on the slide switch (S1), and shine
light on the solar cell (B2). There will be activity from all six forms of
output. If the motor does not spin, then give it a push with your finger
to start it, or remove the fan.
!
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over the motor.
!
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over the motor.
To learn more about how circuits work, visit www.snapcircuits.net or page 85 to find out about our Student Guides.