Elenco LIGHT - Manual (Page 58)

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Project 116 Buzzer
Project 118
Photo Light & Motion
Project 119
Slow Light &
Motion
Use the circuits from projects 116-117,
but replace the 0.1
µ
F capacitor (C2)
with the 100 µ F capacitor (C4), “+” to
the right. Turn the switch on and
patiently wait. The speaker will beep
and the color LED (D8) will flash every
5-20 seconds, depending on the
resistors.
Use the circuits from projects 116-117, but add the phototransistor (Q4)
across base grid locations B2-B4 (between RV and R1, “+” on the left), on
level 3. Vary the amount of light on the phototransistor to change the
sound, while also varying RV.
Light Up the Fan Project 120
This circuit is an
oscillator, which uses
feedback to control
the pitch of the
sound.
Build the circuit as shown, place the glow fan on the motor
(M1), and turn on the slide switch (S1). Place the circuit in
a dark room and push the press switch (S2) to spin the fan.
The color LED (D8) lights up the spinning fan.
!
WARNING: Moving parts. Do not
touch the fan or motor during
operation.
The circuit with the color LED is not
electrically connected to the circuit with the
motor. This was done because the motor
produces electrical pulses as it spins, and
these pulses can confuse the color LED.
Build the circuit as shown and
turn on the switch (S1). Move
the lever on the adjustable
resistor (RV) to vary the pitch
of the buzzing sound.
Project 117
Higher Pitch Buzzer
Use the preceding circuit, but place the 5.1k Ω resistor directly over the
100k
Ω
resistor using a 1-snap. The pitch of the tone is higher now, but the
circuit may not make noise on all settings for the adjustable resistor.