Elenco Projects 102-305 - Manual (Page 33)

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Project #190
OBJECTIVE: To build a transistor oscillator that can make a
foghorn sound.
Hissing Foghorn
Project #191
Hissing & Clicking
OBJECTIVE: To build an adjustable clicking oscillator.
Modify the circuit in project #190 by replacing
the 100k
Ω resistor (R5) with the photoresistor
(RP).
Move the adjustable resistor (RV) setting until
you hear hissing sounds, and then shield the
photoresistor while doing so and you hear
clicking sounds.
OBJECTIVE: To build a human oscillator.
Build the circuit on the left and
move the adjustable resistor (RV)
setting. Sometimes it will make a
foghorn sound, sometimes it will
make a hissing sound, and
sometimes it will make no sound
at all.
Project #192
Video Game
Engine Sound
Remove the photoresistor (RP) from the
circuit in project #191 and instead touch your
fingers between the contacts at points A4 and
B2 on the base grid while moving the
adjustable resistor (RV). You hear a clicking
that sounds like the engine sound in auto-
racing video games.