Elenco Snap Circuits Motion - Manual (Page 75)

Build the circuit as shown and turn on the switch (S1).
The color LED (D8) will be blinking and you hear
beeping from the speaker (SP2). The adjustable
resistor (RV2) can adjust the sound and LED
brightness a little.
Project 153 Blinker Beeper Project 154
Blinker
Blinker
Use the preceding circuit, but replace the
speaker (SP2) with the red/yellow bicolor
LED (D10, in either orientation). Now the
red/yellow LED will also be blinking.
Build the circuit as shown and turn on the switch (S1). The color LED
(D8) and red/yellow bicolor LED (D10) will both be blinking. The color
LED will be brighter than in the preceding circuit. The adjustable resistor
(RV2) can change the color LED brightness a little.
The red/yellow LED is controlled by the color LED using the transistor
(Q2). If you remove the color LED from the circuit then the red/yellow
LED will not light. Removing the red/yellow LED will not affect the color
LED.
Try swapping the locations of the color & red/yellow LEDs, reversing
the orientation of the red/yellow LED, or replacing the red/yellow LED
with the speaker (SP2).
Project 155 Blinker Control
The color LED (D8) has a
microcircuit that changes the
light colors. As it does this, it
changes the current through
the circuit. The transistor (Q2)
amplifies the changing
current and uses it to control
the speaker (SP2).
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