Students of electronics typically work through some common concepts as they go, building knowledge and skills that allow them to tackle more ambitious projects as they make progress. Early on, study and effort will generally focus on the design and building of especially simple circuits, with the fundamental principles of electronics being demonstrated and absorbed along the way. Over time, students who have become more confident and capable will tend to branch out, often pursuing particular interests, to some extent, as they advance further. In many cases, this will mean learning how electronic components of the most basic, familiar kinds can vary in their real-world forms of embodiment.
Just about every student who has ever looked into electronics, for example, will already be comfortable, to at least some extent, with resistors. A resistor is one of the fundamental types of electronic components, adding, as the name suggests, a measured amount of resistance to any circuit of which it is part. The resistors that beginning students regularly work with, though, represent only a fraction of what such parts can look like and accomplish in general.
In many cases, for example, parts that are suitable for the projects tackled by beginners will be much less so under certain, more specific circumstances. Every resistor is manufactured to particular levels of tolerance, and testing at the point of production will normally be used to ensure that this standard is achieved. When the usual levels of tolerance are too coarse, given the demands of a particular project, precision resistors that go beyond them will often be used instead. While it might be relatively rare to need such heightened precision, having access to parts of this kind can enable projects that would otherwise be impossible.
While the projects that most students turn to are normally designed to accommodate a certain manual style of work, many others in the real world revolve around more advanced production techniques. Instead of working with resistors with two long, relatively unwieldy leads, many projects will therefore include the use of surface mount resistors that are designed to accommodate that approach to assembly.
Another project might need to employ a high power resistor to account for much greater levels of voltage and current than the usual parts could handle. Still another could make use of a current sense resistor that adds barely any resistance at all, instead making it possible to monitor amperage through the varying voltage it creates. While beginners therefore do well to become very familiar with resistors in their most basic forms, that should never be taken as the final word on the matter.