Elenco Snap Circuits Motion - Manual (Page 49)

Build the circuit and turn on the slide switch (S1). A siren sounds, and
two red lights are on.
Variants: You can change the sound by removing the 1-snap and 2-
snap wires that are at point A, or by moving them to be across points B
& C, or across points A & D. You can also reverse the orientation of the
red/yellow bicolor LED (D10); then it produces yellow light instead of
red light.
Project 81 Double Red Siren
Build the circuit and turn on the slide switch (S1). A siren sounds, and
two red lights are on.
Variants: You can change the sound by removing the 1-snap and 2-
snap wires that are at point C, or by moving them to be across points A
& B, or across points A & D. You can also reverse the orientation of the
red/yellow bicolor LED (D10); then it produces yellow light instead of
red light.
Project 82 Double Lights Siren
The color LED (D8) doesn’t
change colors because the
alarm IC (U2) is constantly
resetting it.
-48-
The color LED (D8) is mostly red color
because in this arrangement there is
barely enough voltage across it to turn it
on, and red light is easier for it to produce
than green or blue. There will be more
green and blue if your batteries are
strong, and less or none if they are weak.
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