Data Sheet

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7. Bi-directional LED
Build the circuit to the left and turn on the switch (62).
You will see the bi-directional LED (71) is on with red
light. Disconnect the switch (62) and the bi-directional
LED (71) will be turned off. Reverse the direction of the
bi-directional LED (71) and you will see the bi- directional
LED (71) is turned on with blue light. 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
Replace the switch (62) with the press switch (61),
then press the press switch (61) and you will see the
bi-directional LED (71) in on with red light. Release the
press switch (61) and the bi-directional LED (71) will
be off. Reverse the direction of the bi-directional LED
(71) and it will turn on blue when you press the press
switch (61). Bi-directional LEDs can be used as sensors
that indicate which direction current is owing.