Circuitmess Wacky Robot Marv Instructions Manual page 12

From the invisible spectrum
to the Eiffel Tower
LEDs are semiconductor electronic components
that convert an electrical signal into light.
LEDs are polarized, so we must be cautious
about how we place them. Current flows in
only one direction, so if you place them in the
opposite direction, the diode won't function.
+
Rounded
part
You can recognize the polarity by the shapes of the
sides of the diode. The positive side is rounded and
called the anode, while the negative side is flat and
called the cathode. Electrical energy always travels
from the anode to the cathode, never vice versa.
-
+
Cut-off
Rounded
part
part
-
Cut-off
part