PAGE 092 OF 150 · DISPLAYS & INDICATORS
Status LED Colour Conventions
Colours often suggest ready, warning or fault.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
Common meanings
- Red: fault, stop, danger or alarm.
- Amber or yellow: warning, caution or standby.
- Green: OK, ready or running.
- Blue: information or a special status, such as wireless on.
- White: general or neutral status.
Patterns
Flashing normally means attention or activity, and faster flashing implies more urgency. Steady light means a stable state.
Accessibility
Some people cannot tell red from green, so add labels, symbols, positions or flash patterns instead of relying on colour alone.
REMEMBER
A seven-segment digit is seven small LEDs arranged to draw numbers.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
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