User Manual

Project 48
Bi-Color Light
Turn on the slide switch (S1); the display on the LED-MC (U29) shows
“00”. Press the A button on the selector (S8) to increase the ones digit
on the display, and press the C button on the selector to increase the
tens digit on the display. When the display shows “21”, press the B
button on the selector to start.
The red/yellow LED (D10) will be on continuously, but changing colors
at varying speed.
Modify the preceding circuit to include the speaker (SP2), as shown.
The circuit works the same way but now includes sound. The sound will
not be very loud.
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The red/yellow LED (D10) is a bi-color LED, which
means it has two LEDs (red & yellow) inside,
connected in opposite directions.
Notice that when D10 is changing colors quickly,
its red and yellow colors tend to blend into orange.
Project 49
Bi-Color Light
& Sound