Elenco Electronics EP-130 - Page 115

-115
-
V
CO
? What’s that? V
CO
stands for volta
g
e
c
ontro
ll
e
d
osc
ill
ator, an
d
as t
h
e name
i
mp
li
es, t
his
oscillator changes its oscillation frequency accordin
g
to t
h
e vo
l
tage app
li
e
d
to t
h
e c
i
rcu
i
t.
Th
e c
i
rcu
it
c
reates two different output si
g
nals that hav
e
tr
i
an
g
u
l
ar an
d
square waves
.
When you finish the wiring sequence, slide the switc
h
to position A to turn on the power. Turn the control
s
lowly while you listen to the sound
f
rom th
e
earphone. The sound becomes lower when you tur
n
the control clockwise
.
T
urn
i
n
g
t
h
e contro
l
c
h
an
g
es t
h
e vo
l
ta
g
e at term
i
na
l
27, w
hi
c
h
c
h
an
g
es t
h
e 0.01
μ
F
capac
i
tor
’
s c
h
ar
gi
n
g
and dischar
g
in
g
times, which chan
g
es the oscillato
r
f
requency. The output signal
f
rom the
f
irst operational
ampli
f
ier is a triangular wave signal is at terminal 67
,
and is applied to terminal 65 o
f
the second ampli
f
ier
.
The second am
p
li
f
ier acts as a com
p
arator, an
d
pro
d
uces a square wave s
i
gna
l
at term
i
na
l
64
.
No
t
es
:
EXPERIMENT #96: VC
O
Wirin
g
S
equence:

7
9
-
63
-2
6
-1
3
1

2
7-
8
7-
89

46-9
1

47-7
6

86
-
9
2-1
09
-
6
4

6
5-7
8

66
-
80
-
83
-
85

6
7-1
0
2-7
7

68
-
90
-
101
-75

69-88-8
1

8
4-7
0
-1
34

121-1
35

122
-
132

124-11
9
-2
8
-4
8
-
9
4-
8
2-14-EARPH
O
NE

11
0
-
93
-1
3
-EARPH
O
N
E
S
chematic