Data Sheet
-99-
202. Relative Light Intensity
Build the circuit, turn on the switch (62), and the lamp (76) and the
colorful LED (72) will be turned on at the same time. Decibels can also
be used to compare light intensity levels. For instance, if the colorful
LED (72) was twice as bright as the lamp (76), the this would lead to
a 10*log(2) = 3dB difference between the light intensity of the colorful
LED (72) and the lamp (76). You can nd the log function on your typical
scientic calculator.
203. Integrated Circuits (ICs)
Replace the switch (62) with the press switch (61) in project #202,
then press the press switch (61) and the lamp (76) and the colorful LED
(72) will be turned on at the same time.
There is often the need to build simple as well as more complex circuits
like this into very small devices (e.g. a garage door opener, a TV remote,
etc.). Oftentimes this is done by making an Integrated Circuit (IC) board.
ICs are small pieces of semiconducting material that is designed to
provide the same circuit function as in this project or any other circuit.
You can think of an IC circuit like a collection of resistors, capacitors,
transistors, etc., all stuffed into a tiny chip and designed to provide the
same circuit function as with actual physical resistors, capacitors, and
transistors.
204. Fan/Motor Speed
Replace the lamp (76) in project #202 with the motor (95). Now If you
turn on the switch (62) you will see the colorful LED (72) is on and the
motor (95) is spinning too. Motor speed is measured in Revolutions per
Minute, or RPMs. How fast do you think your motor (95) is spinning?
205. Poles in an AC Motor
In project #202, replace the switch (62) with the press switch (61),
replace the lamp (76) with the motor (95). Now if you press the press
switch (61) you will see the colorful LED (72) is shining and the motor
(95) is spinning too. Motors that run off of AC current (i.e. ones that
you plug into the outlets in your house) have poles, similar to the poles
in a magnet. Unlike a magnet, though, these poles are created by
windings of magnet wire.
WARNING: Moving parts. Do not
touch the motor during operation. Do
not lean over the motor.
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1st level