Manual

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This circuit changes the intervals between each
sound according to the amount of light falling on the
CdS cell. The sound changes continuously as you
alter the light intensity.
Build the circuit, and set the switch to position A to
turn on the power. The speaker makes a sound. To
change the sound, move your hand over the CdS.
You can calculate the approximate value of the
frequency of the signal by using the equation 1/2 x
C1 x R1. However, R1, in this project, is the CdS
and is not constant. By changing C1 you can
change the value of the output frequency. In this
experiment, another operational amplifier is used as
a buffer, so the light-controlled sound part of the
circuit is not affected by the speaker sound.
Notes:
EXPERIMENT #103: LIGHT-CONTROLLED SOUND
Wiring Sequence:
o 1-29
o 2-30
o 3-64-65
o 5-86-110-119-124
o 15-68-109
o 16-66-67-88
o 63-131
o 69-87-85
o 70-134
o 121-135
o 122-132
Schematic
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