Manual

-66-
L
isten to the sound this project makes. Take your
time and check your work because there are a lot of
w
iring steps. Once you’ve finished, set the switch to
position A. What are you hearing? From looking at
the schematic, can you explain how the circuit
produces this sound?
This circuit has two multivibrators, one with PNP
transistors, and one built with NAND gates. You
have used both types before, but not together in the
same circuit. The NAND gate multivibrator affects
the operation of the transistor multivibrator, which
sends its output through the NPN transistor to the
audio amplifier. You hear the resulting sound from
the speaker.
By substituting a different value for the 470mF
capacitor, you can change the sound this circuit
makes. See what happens when you try different
values for the 10kW resistor and the 0.05mF
capacitor.
N
otes:
EXPERIMENT #49: MACHINERY SOUND
Wiring Sequence:
o 1-29
o 2-30
o 3-48
o 5-50-51-53-54-72-80-62-121
o 40-109-85
o 41-106-79
o 42-45-47-131-115-49
o 43-105-81
o 44-110-83-71
o 46-84
o 57-56-77-117
o 58-59-60-75-78
o 61-73-76-118
o 74-82-86-116
o 119-132
Schematic
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