Status indicators on all sorts of equipment
Traffic lights and signals
Motorcycle and Bicycle lights
Toys and recreational sporting goods, such as the Flashlight
Railroad crossing signals
Flashlights. Some models that do not even use batteries are of this type.
Light bars on emergency vehicles.
Elevator Push Button Lighting
Thin, lightweight message displays at airports and railway stations and as destination displays for trains, buses, trams and ferries.
Red or yellow LEDs are used in indicator and alphanumeric displays in environments where night vision must be retained: aircraft cockpits, submarine and ship bridges, astronomy observatories, and in the field, e.g. night time animal watching and military field use.
Red, yellow, green, and blue LEDs can be used for model railroading applications
Remote controls, such as for TVs and VCRs, often use infrared LEDs.
In optical fiber and Free Space Optics communications.
In dot matrix arrangements for displaying messages.
Glow lights, as a more expensive but longer lasting and reusable alternative to Glow sticks.
Movement sensors, for example in optical computer mice
Because of their long life and fast switching times, LEDs have been used for automotive high-mounted brake lights and truck and bus brake lights and turn signals for some time, but many high-end vehicles are now starting to use LEDs for their entire rear light clusters. Besides the gain in reliability, this has styling advantages because LEDs are capable of forming much thinner lights than incandescent lamps with parabolic reflectors. The significant improvement in the time taken to light up (perhaps 0.5s faster than an incandescent bulb) improves safety by giving drivers more time to react.
Backlighting for LCD televisions and displays. The availability of LEDs in specific colors (RGB) enables a full-spectrum light source which expands the color gamut by as much as 45%.
New stage lighting equipment is being developed with LED sources in primary red-green-blue arrangements.
Lumalive, a photonic textile
LED-based Christmas lights have been available since 2002, but are only now beginning to gain in popularity and acceptance due to their higher initial purchase cost when compared to similar incandescent-based Christmas lights. For example, as of 2006, a set of 50 incandescent lights might cost $2.00 USD, while a similar set of 50 LED lights might cost $10.00 USD. The purchase cost can be even higher for single-color sets of LED lights with rare or recently-introduced colors, such as purple, pink or white. Regardless of the higher initial purchase price, the total cost of ownership for LED Christmas lights would eventually be lower than the TCO for similar incandescent Christmas lights since an LED requires much less power to output the same amount of light as a similar incandescent bulb.
As a medium quality voltage reference in electronic circuits. The forward voltage drop (e.g. about 1.7V for a normal red LED) can be used instead of a Zener diode in low-voltage regulators. Although LED forward voltage is much more current-dependent than a good Zener, Zener diodes are not available below voltages of about 3V.
Computers, for hard drive activity and power on. Some custom computers feature LED accent lighting to draw attention to a given component. Macintosh computers use LEDs to tell the user that it is asleep, by fading in and out. This fading is produced by either a triangular wave or a sine wave generator.