Elenco Electronics EP-130, Manual

Page: 85 / 160

This circuit has a multivibrator connected to a pulse
type oscillator. The multivibrator provides a tremolo
effect (a wavering tone), rather than turning the
oscillator completely on and off.
After you build the project, you can use the control to
vary the base current supplied to the NPN transistor.
This changes the charge/discharge rate of the 0.1
μ
F
and 0.05
μ
F capacitors, and the frequency of the
pulse oscillator.
The key works to turn the entire circuit on and off.
You can replace it with the slide switch. Also, you can
change the tonal range by changing the 10
μ
F and
3.3
μ
F capacitor values.
Try using the switch or the key to add extra
components to the circuit (like an extra capacitor in
parallel with the 10
μ
F or 3.3
μ
F), so you can change
from one tonal range to another, quickly. These
changes will make a more complete organ from this
project. Be sure to keep notes on what you do.
Notes:
EXPERIMENT #67: ELECTRONIC ORGAN
-85-
Wiring Sequence:
o
1-29
o
2-30
o
3-47-106
o
4-74-45-42-119
o
5-105-109
o
27-46-110
o
28-86
o
40-111-80
o
41-114-78
o
43-113-82
o
44-112-87-76
o
77-75-81-79-48-138
o
73-85-88
o
120-137
Schematic