What does "through-hole technology" refer to in soldered assemblies?

Through-hole technology refers to a method of connecting components to a circuit board by inserting component leads through holes drilled in the board. Once the leads are through the holes, they are soldered on the opposite side, securing the components in place. This technique is pivotal in traditional electronic assembly processes, especially for components that require robust mechanical strength or are subject to physical stress.

The description aligns well with the definition of through-hole technology, emphasizing the process of soldering as a means to create strong electrical and mechanical connections. It is commonly employed in applications where durability is crucial, such as in power supplies and high-reliability electronics.

In contrast, the other options present different concepts that do not pertain to through-hole technology. For example, surface mount technology refers to a different method of attaching components directly onto the surface of the circuit board without requiring drilled holes. Solder paste application and the etching of circuit boards are processes used in the fabrication and assembly of printed circuit boards but do not define how components are connected in through-hole technology specifically.