What is smd?

"SMD" can refer to a couple of different things depending on the context. Here are some of the most common meanings:

1. Surface-Mount Device (SMD):

   • In electronics, an SMD refers to components that are mounted directly onto the surface of a printed circuit board (PCB).
   • SMD components are used in Surface-Mount Technology (SMT), which allows for more compact and efficient electronic designs compared to through-hole technology, where components have leads that go through the board.
   • They include resistors, capacitors, and integrated circuits, and are smaller than their through-hole counterparts.

2. Synchronous Digital Hierarchy (SDH) Multiplexer (SMD):

   • Used in telecommunications, an SMD in this context is a product or technology used in managing high-speed digital signal transmission over optical fiber.
   • It is used to multiplex multiple digital signal inputs into a single signal for transmission.

3. SMD in File Formats:

   • SMD can also refer to certain file formats used in various applications or technologies. For example, in SEGA Genesis, it’s a type of ROM file for emulation use.

If you're referring to something different with "SMD," could you please provide more context?