Elenco Electronics EP-130, Manual, Page: 23 / 160

-23-
The sound that this circuit produces will remind you
of the scary music you hear in horror movies. After
wiring the project, use your special light shield and
your hand to change the amount of light that falls on
the CdS cell. The music changes in pitch.
The pitch of a sound is determined by the frequency
of the sound wave - the number of cycles of
electromagnetic energy per second. The amount of
light of the CdS cell determines the resistance value
of the cell. More resistance from the cell slows down
the frequency of the music sound waves. The basic
“music” is produced by the oscillator circuit.
When a circuit controls the frequency of an
oscillator, we call it FM or frequency modulation. An
FM radio signal is something like this, but at much
higher frequencies.
Notes:
EXPERIMENT #12: HORROR MOVIE SOUND EFFECTS
Wiring Sequence:
o
1-29
o
2-30
o
3-47-106
o
4-74-45-42-119
o
5-103-105
o
15-86
o
16-46-104
o
40-113-80
o
41-112-78
o
44-114-83-76
o
120-48-81-79-75-77
o
73-85-84
Schematic