Elenco Electronics 202 - Manual (Page 27)

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Project #27
The Transistor
OBJECTIVE: To compare
transistor circuits.
Project #28
The Transistor (II)
Place the fan on the motor (M1)
and turn on the slide switch (S1)
- nothing happens. Press the
press switch (S2), the lamp (L2)
lights dimly and the motor spins.
The lamp will be brighter if you
remove the fan from the motor.
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.
OBJECTIVE: To compare transistor circuits.
Compare this circuit to project
#27. It works the same way, but
the lamp (L2) is brighter here and
the motor (M1) 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.
Project #29
The Transistor (III)
OBJECTIVE: To compare transistor circuits.
Project #30
The Transistor (IV)
Compare this circuit to project
#28. It works in a similar way,
but the motor (M1) does not spin
even though the lamp (L2) is
bright. But the lamp is not as
bright here as in project #28.
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.
OBJECTIVE: To compare transistor circuits.
Compare this circuit to project
#29. It works in a similar way,
the lamp (L2) is off but the motor
(M1) spins. But the motor does
not spin as fast as in project #27.
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.
!
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.