Elenco Electronics 202 - Manual (Page 71)

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Project #157
OBJECTIVE: To build a transistor oscillator that can make a
foghorn sound.
Hissing Foghorn
Project #158
Hissing & Clicking
OBJECTIVE: To build an adjustable clicking oscillator.
Modify the circuit in project #157 by replacing
the 100k
Ω resistor (R5) with the photoresistor
(RP).
Move the adjustable resistor (RV) setting until
you hear hissing sounds, and then completely
cover the photoresistor with your hand 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 #159
Video Game
Engine Sound
Remove the photoresistor (RP) from the
circuit in project #158 and instead touch your
fingers between the contacts at points A4 and
B1 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.