Elenco XP&trade - Manual (Page 12)

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Project A1 Electric Light
Snap Circuits ® uses electronic blocks that snap onto a clear plastic
grid to build different circuits. These blocks have different colors
and numbers on them so that you can easily identify them.
Build the circuit shown on the left by placing all the parts with a
black 1 next to them on the board first. Then, assemble parts
marked with a 2. Install three (3) “AA” batteries (not included) into
the battery holder (B3) if you have not done so already.
When you turn on the slide switch (S1), current flows from the
batteries through the switch, red LED (D1), and 100
Ω resistor (R1),
and back to the batteries. Turning on the switch completes the
circuit. When the switch is off, the current can no longer flow back
to the battery, so the red LED goes out.
The red LED is just like the ones used in electronic products
throughout your home.
+
Placement Level
Numbers
+
Use the circuit built in project A1, but replace the
100
Ω
resistor (R1) with the 1k
Ω
resistor (R2). The
circuit works the same, but the red LED (D1) will
not be as bright.
Now replace the 1k
Ω
resistor with the 10k
Ω
resistor (R4). The LED will be dim now.
Now replace the 10k
Ω
resistor (R4) with the 100k
Ω
resistor (R5). The 100k Ω has very high resistance,
so you may not see any light from the LED.
Take the circuit into a really dark room or curl your
fingers around the LED to block the surrounding
light. Now you see that the LED is on, though very
dim.
Project A2 Controlling Electricity
Snappy says resistors are used to control or
limit the flow of electricity in a circuit. Higher
resistor values reduce the flow of electricity in a
circuit.
In this circuit, the resistors are used to adjust the
LED brightness, to limit the current so the
batteries last longer, and to protect the LED
from being damaged by the batteries.
What is Resistance? Take your hands and rub
them together very fast. Your hands should feel
warm. The friction between your hands
converts your effort into heat. Resistance is the
electrical friction between an electric current
and the material it is flowing through.