Elenco LIGHT - Manual (Page 49)

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Project 87 Blinking Beeping
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. The sound will not
be very loud.
Project 89 Blinking Control
Build the circuit as shown and turn on the
switch (S1). The color LED (D8) and white
LED (D6) will both be blinking. The color LED
will be brighter than in the preceding circuit.
The white LED is controlled by the color LED
using the transistor (Q2). If you remove the
color LED from the circuit then the white LED
will not blink.
Project 90
Blinking Control
Beeping
Use the preceding circuit, but replace the
white LED (D6) with the speaker (SP). Now
the blinking LED controls a beeping sound,
but the sound will not be very loud.
Project 88
Blinking
Blinking
Use the preceding circuit, but replace the
speaker with the red LED (D1). Now the
red LED will also be blinking.
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 (SP).