Elenco Projects 102-305 - Manual (Page 55)

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Project #252 Storing Electricity
OBJECTIVE: To store electricity in a capacitor.
Project #253 Lamp Brightness Control
OBJECTIVE:
To use a transistor combination to
control a lamp.
OBJECTIVE: To make an electric
fan using a transistor circuit.
Use the circuit from project #253.
Replace the lamp (L1) with the
motor (M1) and install the fan. By
controlling the adjustable resistor
(RV), the speed of the fan
changes. Now you can make
your own speed changing
electric fan.
Here is a combination with two
transistors. This combination
increases the amplifying power. By
changing the resistance, the current
at the base of the transistor is also
changed. With this amplifying ability
of the combination, there is a greater
change of current to the lamp (L1).
This changes the brightness.
Turn the slide switch (S1) on and connect points A & B with a 2-snap
wire. The green LED (D2) will flash and the 470
μ F capacitor (C5) will
be charged with electricity. The electricity is now stored in the
capacitor. Disconnect points A & B. Connect points B & C and there
will be a flash from the 6V lamp (L2).
The capacitor discharges through the resistor to the base of the NPN
transistor (Q2). The positive current turns on the transistor like a
switch, connecting the lamp to the negative (–) side of the batteries.
The light will go out after the capacitor discharges, because there is no
more current at the base of the transistor.
Project #254
Electric Fan
!
WARNING: Moving parts.
Do not touch the fan or
motor during operation. Do
not lean over the motor.
Visit www.snapcircuits.net or page 74 to learn about Snap Circuits ® upgrade kits, which have more parts and circuits.