Elenco Snap Circuits® Deluxe Sound & Light Combo - Manual (Page 78)

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Project 143 Series Lights
Project 144 Wacky Sound Control
This circuit has all the parts
connected in a series. Swapping
the locations of any parts in the
circuit (without changing the
direction of their “+” side) will not
change how the circuit works. Try it.
The LEDs are dim because the
batteries need to overcome the
activation voltage level for every
LED in the series before any can
light. That doesn’t leave much
voltage to overcome the resistance
in the circuit. If you replace one of
the LEDs with a 3-snap, the others
will be much brighter. Try it.
Build the circuit and turn on the switch
(S1). Place the circuit in a dimly lit room.
Some of the LEDs (D1, D6, & D8) will
be blinking, but none will be very bright.
If nothing lights then replace your
batteries.
The LEDs are blinking because a color-
changing circuit in the color LED is
turning that LED on and off, which also
affects the other LEDs.
Build the circuit and turn on the slide switch (S1). Vary the amount of
light on the phototransistor (Q4) and push the press switch (S2) to
change the sound.
SCC-350_Manual_Part_B.qxp 7/25/14 2:05 PM Page 22