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Project #252 Storing Electricity
Project #253
Lamp Brightness Control
OBJECTIVE:
To use a transistor combination
OBJECTIVE: To make an
electric fan using a
Use the circuit from Project 253.
Replace the lamp (L2) with the
motor (M1) and install the fan. By
controlling the adjustable
resistor, 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. This
changes the brightness.
Turn the switch on and connect point A and B with a 2-snap wire. The
green LED will flash and the capacitor will be charged with electricity.
The electricity is now stored in the capacitor. Disconnect point A and
B. Connect point B and C and there will be a flash from the 6V lamp.
The capacitor discharges through the resistor to the base of the NPN
transistor. 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
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