Elenco Electronics EP-130, Manual

Page: 107 / 160

Here’s the operational amplifier version of the
electronic metronome from Project 9 (“Electronic
Metronome”). Slide the switch to position B, and
connect the wires carefully - this project is much
more complicated than most of the others. When
you finish assembling the circuit, set the control to
the 12 o’clock position and slide the switch to
position A to turn on the power. You’ll hear a pip
sound from the speaker at fixed intervals. Now
slowly rotate the control clockwise, and the beats
come faster.
Now take a look at the schematic. IC 1 and IC 2 are
used as astable multivibrators, as in our last project.
But you’ll notice that IC 1 uses diodes to generate
short pulses and the control is used to adjust the
speed of the pulses. The transistor turns on each
time a pulse is generated, and produces a sound.
Notes:
EXPERIMENT #88: MUSICAL TEMPO GENERATOR
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Wiring Sequence:
o
1-29
o
2-30
o
3-114
o
5-47
o
27-127
o
28-77
o
46-80-84
o
79-70-108-116-48-121
o
63-131
o
89-91-113-64
o
65-90-107
o
86-92-66
o
78-76-83-88-67
o
68-115-125-128
o
82-87-69
o
75-126
o
85-81-119-124
o
122-132
Schematic