A surface mount LED, also known as an SMD LED, is a light emitting diode which is directly mounted on and soldered to a PCB board. Without the leads and surrounding packaging of a standard LED, a surface mount LED is actually quite small, best handled by automated assembly equipment instead of a human. Without the epoxy of a standard light emitting diode enclosure to focus the generated beam, a surface mount LED also has a very wide viewing angle, generally from 100 to 140 degrees.
Like a standard light emitting diode, a surface mount LED gives off almost no heat. It also typically has similar low voltage and low current requirements. They are commonly used to indicate device status on computer motherboards, routers, hard drives, USB flash drives and any other application where physical space is at a premium.
On a larger scale, surface mount LEDs are used to create some indoor display screens. Huge numbers of the diodes can be arranged in tight clusters of red, green and blue, so that a variety of colors can easily be generated. The technology in these screens, which may be found in stores and other businesses, is also making its way into much larger outdoor displays.
The term surface mount LED may also refer to a physical package of multiple LEDs, often 10 or more, which is designed to be a replacement for an exterior incandescent bulb-based automotive light. In this case, surface mount reflects the ease of mounting such a light fixture on the surface of a vehicle. These bright LED lights are generally used for turn signals, tail lights and brake lights.