Surface-mount technology (SMT:printing+chip mounter+reflow oven) is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD). In the industry it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Both technologies can be used on the same board for components not suited to surface mounting such as transformers and heat-sinked power semiconductors.

An SMT((printing+chip mounter+reflow oven)) component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.