Elenco Snap Circuits SOUND &reg - Manual (Page 7)

About Your Snap Circuits ® SOUND Parts
LED
-6-
The speaker (SP) converts electricity into sound
by making mechanical vibrations. These
vibrations create variations in air pressure, which
travel across the room. You “hear” sound when
your ears feel these air pressure variations.
SPEAKER
Speaker (SP2)
Color LED
(D8)
The color LED (D8) is a light emitting diode, and
may be thought of as a special one-way light
bulb. In the “forward” direction, (indicated by the
“arrow” in the symbol) electricity flows if the
voltage exceeds a turn-on threshold (about 1.5V
for red, about 2.0V for green, and about 3.0V for
blue); brightness then increases. The color LED
contains red, green, and blue LEDs, with a micro-
circuit controlling then. A high current will burn
out an LED, so the current must be limited by
other components in the circuit. LED’s block
electricity in the “reverse” direction.
CAPACITOR
The 0.1 m F, 1 m F, and 470 m F capacitors (C2, C7,
& C5) can store electrical pressure (voltage) for
periods of time. This storage ability allows them
to block stable voltage signals and pass
changing ones. Capacitors are used for filtering
and delay circuits.
Microphone (X1)
The microphone (X1) is actually a resistor that
changes in value when changes in air pressure
(sounds) apply pressure to its surface.
MICROPHONE
The photoresistor (RP) is a light-sensitive
resistor, its value changes from nearly infinite in
total darkness to about 1000
W when a bright light
shines on it.
Photoresistor (RP)
Capacitors (C2, C5, & C7)
TRANSISTORS
ELECTRONIC MODULES
The NPN transistor (Q2) is a component that
uses a small electric current to control a large
current, and is used in switching, amplifier, and
buffering applications. Transistors are easy to
miniaturize, and are the main building blocks of
integrated circuits including the microprocessor
and memory circuits in computers.
The keyboard (U26) contains resistors,
capacitors, switches, and an integrated circuit. It
can produce two adjustable audio tones at the
same time. The tones approximate musical
notes, and may not be exact. The tone of the
green keys can be adjusted with the tune knob
or using external resistors and capacitors. A
schematic for it is available at
www.snapcircuits.net/faq.
Connections:
(+) - power from batteries
RES - resistor freq adjust
CAP - capacitor freq adjust
OUT - output connection
(–) - power return to batteries
See projects 1, 6, & 25 for example of proper connections.
NPN Transistor (Q2)
Keyboard (U26)