Question: Information: - A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components capacitors, resistors or active devices are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate. - Through-hole technology, also spelled "thru-hole", refers to the mounting scheme used for electronic components that involves the use of leads on the components that are inserted into holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side either by manual assembly (hand placement) or by the use of automated insertion mount machines. - Surface - mount technology ( SMT ) is a method for producing electronic circuits in which the components are mounted or placed 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 , with the through - hole technology used for components not suitable for surface mounting such as large transformers and heat - sinked power semiconductors . An SMT 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 . - An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components. Given the information, choose the subject and object entities that have the relation of 'subclass of'.
Answer:
surface-mount technology , electronic component