Elenco Electronics EP-130 - Falling Bomb

-10
7-
H
ere
’
s anot
h
er s
i
ren t
h
at a
l
ters
i
ts
pi
tc
h
.
Th
e s
i
ren we
built in our last experiment alters pitch from low t
o
high, but this one alters its pitch from high to low an
d
finally stops making any sound. When it stops, pres
s
the key and the siren sound will start a
g
ain.
Set the switch to position B and put to
g
ether th
e
c
ircuit. When you finish the wiring, slide the switch to
position A to turn on the power. You hear a high
-
pitched siren sound that becomes pro
g
ressivel
y
lower, it sounds like a
f
allin
g
bomb. Press the key to
s
tart the sound a
g
ain.
Lik
e t
h
e s
i
ren
i
n our
l
ast ex
p
er
i
ment, t
hi
s s
i
ren use
s
I
C
1 as a buffer and I
C
2 as an astable multivibrator
.
The capacitor
C
and the resistor R change the pitch
o
f
the siren sound. The pitch adjusts slowly when you
increase the values of
C
and R, and adjusts quickl
y
when you decrease their values. Try usin
g
the 3.3
μ
F
c
apacitor for
C
and notice how the pitch changes.
N
otes:
EXPERIMENT #88: FALLING BOM
B
Wiring Sequence:

1-29

2
-
30

3
-11
6

5-84-94-106-70-121

63-113-131-138

64-90-92-115

65-105-89

66
-
82
-
83
-
91

68
-
6
7-
81

93
-
69
-
114
-
13
7

119
-
124

122
-
132
S
chematic