LED array may include controlling circuits within the same package, which may range from a simple resistor, blinking or color changing control, or an
addressable controller for RGB devices.
Higher-powered white-emitting devices will be mounted on heat sinks and will be used for illumination.
Alphanumeric displays in dot matrix or bar formats are widely available.
Special packages permit connection of LEDs to optical fibers for high-speed data communication links.
Flashing LEDs are used as attention seeking indicators without requiring external electronics. Flashing LEDs resemble standard LEDs but they
contain an integrated?voltage regulator and a multivibrator circuit that causes the LED to flash with a typical period of one second.
In diffused lens LEDs, this circuit is visible as a small black dot. Most flashing LEDs emit light of one color, but more sophisticated devices can flash
between multiple colors and even fade through a color sequence using RGB color mixing.