Elenco 130-in-1 Electronics Playground - Manual (Page 122)

-122-
White noise is a noise that has a wide frequency
range. One kind of white noise is the static noise you
hear when you tune your FM radio to an area with
no station. When you play electronic musical
instruments, you can use white noise, a normally
useless noise, as a sound source.
When you complete building this circuit, set the
switch to position A to turn on the power. Look at the
schematic. You will use the noise that is generated
when you apply a reverse voltage to the base and
the emitter of transistor Q1.
IC 1 acts as an oscillator. The output of this oscillator
is rectified by diodes D1 and D2, and flows to Q1. IC
2 amplifies the noise so that you can hear it through
the earphone.
Notes:
EXPERIMENT #102: WHITE NOISE MAKER
Wiring Sequence:
64-90-13-EARPHONE
121-114-112-46-47-70-96-84-85-14-EARPHONE
93-48-101
94-111-127
82-88-63-132-126
76-89-65
113-66-81-83
77-91-67-110
68-95-92
69-80-87-86
78-79
109-128-125
119-124
122-131
102-75
Schematic