Elenco Circuit Maker Skill Builder 125 - Manual (Page 26)

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Project #31
Transistor Control
Project #32
Slow & Bright
Project #33
Stop & Shine
Project #34
Murky Motor
!
WARNING: Moving parts.
Do not touch the fan or motor
during operation.
!
WARNING: Moving parts.
Do not touch the fan or motor
during operation.
!
WARNING: Moving parts.
Do not touch the fan or motor
during operation.
Place the fan on the motor (M1)
and turn on the slide switch (S1)
- nothing happens. Push the
press switch (S2), the lamp
lights and the motor spins.
The NPN transistor (Q2) uses
the lamp current to control the
motor current. A small current
through the lamp branch creates
a large current through the
motor branch. They combine in
the transistor and leave through
the 3-snap branch.
Compare this circuit to Project
#31. It works the same way, but
the lamp is brighter here and the
motor is slower.
This time the NPN transistor
(Q2) uses the motor current to
control the lamp current. A
current through the motor
branch creates a larger current
through the lamp branch. They
combine in the transistor and
leave through the 3-snap
branch.
Compare this circuit to Project
#32. It works in a similar way,
but the motor does not spin even
though the lamp is bright. But
the lamp is not as bright here as
in Project #32.
The currents in the motor branch
and 3-snap branch are
combined into the lamp branch.
Since the 3-snap has no
resistance, the current through
its branch will be much larger
than the motor branch current.
Compare this circuit to Project
#33. It works in a similar way,
the lamp is off but the motor
spins. But the motor does not
spin as fast as in Project #31.
The currents in the lamp branch
and 3-snap branch are
combined into the motor branch.
Since the 3-snap has no
resistance, the current through
its branch will be much larger
than the lamp branch current.
CM-125_Manual_031514.qxp_CM-125_Manual_031514 4/2/14 12:19 PM Page 26