Manual

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7. The Bi-directional LED
Build the circuit, press the switch (62), you will see
the bi-directional LED (71) turn on blue. Install the bi-
directional LED (71) in the reverse direction. When
you press the switch (62) the bi-directional LED (71)
will turn on red. Bi-directional LEDs actually have two
diodes in them in opposite directions so current can
ow in both directions. But current is only owing
through one diode at a time, which determines
which color LED lights.
8. Bi-directional LED Sensor
Build the circuit, press the press switch (61) and
the bi-directional LED (71) will ash. If you hold
press switch (61), the bi-directional LED (71) will
turn on blue. Install the bi-directional LED (71) in
the reverse direction, then hold the press switch
(61) and you will see the bi-directional LED (71) turn
on red. Bi-directional LEDs can be used as sensors
that indicate which direction current is owing.
Red Light
Red Light
Blue Light
Blue Light