Elenco Electronics EP-130 - Page 87

-
8
7-
This circuit has a multivibrator connected to a pulse
type oscillator. Rather than turnin
g
the oscillato
r
completely on and off, the multivibrator provides
a
tremolo effect
(
a wavering tone
).
After
y
ou build the circuit, use the control to var
y
th
e
base current su
pp
lied to the NPN transistor. Thi
s
chan
g
es the char
g
e
/
dischar
g
e rate of the 0.
1
μ
F
an
d
0
.
05
μ
F
capacitors, as well the
f
requency o
f
the puls
e
osc
ill
ator
.
The key works to turn the whole circuit on and o
ff.
You can substitute it with the slide switch. B
y
c
h
ang
i
ng t
h
e 10
μ
F
an
d
3.
3
μ
F
capac
i
tor va
l
ues, yo
u
can c
h
ange t
h
e tona
l
range.
Try usin
g
the switch or the key to add additiona
l
components to the circuit (like an extra capacitor i
n
parallel with the 1
0
μ
F
or 3.3
μ
F
)
, so you can alte
r
from one tonal range to another, quickly. These
changes will make a more complete organ
f
rom thi
s
experiment. Be sure to make notes on what you do
.
N
o
t
es
:
EXPERIMENT #
69
: ELE
C
TR
O
NI
C
O
R
G
AN
OSC
ILLAT
OR
Wiring
S
equence
:

1
-
29

2
-30

3
-47-1
06

4-74-4
5
-42-11
9

5
-
10
5-
109

2
7-4
6
-11
0

28
-
86

40
-
111
-
80

41-114-78

43
-
113
-
82

44
-
112
-
8
7-7
6

77-7
5
-
8
1-7
9
-4
8
-1
38

7
3
-
8
5-
88

1
2
0
-1
3
7
S
chematic