Data Sheet

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39. Light Power
Build the circuit to the left, press the switch (62) and the
star LED (70) will be bright but the lamp (76) will be very
dim. Light power can be measured in Watts or Lumens.
Watts refer to how much energy the bulb uses while
Lumens are a measure of the bulb’s light output intensity.
40. Battery Power
Build the circuit shown on the left, then turn on the switch
(62) and you will see the star LED (70) is on. If you touch
the reed switch (83) with magnet (7), the star LED (70)
will go off, but the lamp (76) will turn on. Batteries have
an anode (– side) and cathode (+ side) and are designed to
have a build up of electrons in the anode. When you turn
on the switch (62) in this circuit, it closes the circuit which
allows the build up of electrons to ow out of the anode
and into the cathode enabling current to ow through the
circuit. Due to historical reasons however, conventional
current (sometimes called “positive current”) is actually
said to ow from the cathode to the anode (the opposite
direction that the “negative current” or electrons ow).
41. Motors and Magnetic Fields
Replace the lamp (76) with the motor (95) and press the switch
(62). Now you can control whether the star LED (70) or the
motor (95) is on by moving the magnet (7) close to or away
from the reed switch (83). Now put the magnet (7) near the
motor (95). Note that the magnet (7) is attracted to the motor
(95) at certain locations. This is because motors have magnets
inside them that create a magnetic eld. When a current ows
through this magnetic eld (the circuit is ON), it creates a force
(look up Fleming’s rule) that spins the motor shaft.
WARNING: Moving parts. Do not
touch the motor during operation. Do
not lean over the motor.
!