Elenco 130-in-1 Electronics Playground - Manual (Page 110)

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This is the operational amplifier version of the
electronic metronome from Project 3 (“Electronic
Metronome”). Slide the switch to position B, and
connect the wires carefully - this project is more
intricate than most of the others. When you complete
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 noise from the
speaker at fixed intervals. Now gradually rotate the
control clockwise, and the beats come faster.
Now observe the schematic. IC 1 and IC 2 are used
as astable multivibrators, as in our last experiment.
But you’ll notice that IC 1 uses diodes to generate
short pulses and the control is used to modify the
speed of the pulses. The transistor turns on each
time a pulse is generated, and creates a sound.
Notes:
EXPERIMENT #91: OP AMP METRONOME
Wiring Sequence:
1-29
2-30
3-114
5-47
27-127
28-77
46-80-84
79-70-108-116-48-121
63-131
89-91-113-64
65-90-107
86-92-66
78-76-83-88-67
68-115-125-128
82-87-69
75-126
85-81-119-124
122-132
Schematic