About Your Snap Circuits
®
Parts
LED
White LED (D6)
The
white LED (D6)
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 volt-
age exceeds a turn-on threshold brightness then
increases. A high current will burn out an LED,
so the current must be limited by other compo-
nents in the circuit (Snap Circuits
®
LEDs have in-
ternal resistors added, to protect them in case
you make wiring mistakes). LEDs block electricity
in the “reverse” direction.
COM
Relay:
Coil - connection to coil
Coil - connection to coil
NC - normally closed contact
NO - normally open contact
COM - common
See project 69 for an example of proper connections.
Coil
Coil
NO
NC
The
relay (S3)
is an electronic switch with contacts
that can be closed or opened. It contains a coil that
generates a magnetic field when current flows
through it. The magnetic field attracts an iron arma-
ture, which switches the contacts. See project 69 for
further explanation.
RELAY
Relay (S3)
Two Spring Socket
Two Spring
Socket (?1)
The
two-spring socket (?1)
just has two
springs, and won’t do anything by itself. In this
set it is used to make the build-your-own electro-
magnet, as per page 5. It can also be used by
advanced users to connect other electronic com-
ponents to Snap Circuits
®
for creating your own
circuits.
LED Symbol
Relay Symbol
-8-
The symbols for the parts shown in
this section are used by engineers in
drawings of their circuits, called
schematics. Wires connecting com-
ponents are shown as lines, with a
dot indicating a connection between
lines that cross. Here are schematics
of some of the circuits you will build:
SCHEMATICS
Project 14 Schematic:
Project 27 Schematic:
Project 43 Schematic:
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