The basic electronic components that are combined in so many sophisticated ways tend, themselves, to be fairly simple. What can look like an easily comprehensible matter, at first, however, sometimes turns out to be more complicated upon closer inspection. Likely the simplest-seeming electronic part of all is the resistor, a device which, in its most basic form, is known for doing nothing more than impeding the flow of current through a circuit. In practice, however, resistors vary a great deal from one another to account for the particular requirements of a huge range of potential applications.
In many cases, a simple, inexpensive resistor that adds a certain amount of resistance at a particular level of precision will be all that is required. These tend to be the resistors that many are most familiar with, as commodity-style parts of these kinds crop up in virtually every electronic product and setting. Often distinguished from one another with colorful bands that indicate the Ohm rating of each, parts of these kinds are typically as widely available and affordable as they are useful.
In some cases, however, an improved level of precision will be required. Some currents are so sensitive to current levels that they cannot tolerate deviations from the ideal of even a fraction of a percent. In such cases, precision resistors that go far beyond what commodity parts offer will often be required, with much greater care being taken in the course of their design and manufacturing to make sure that the resistance each affords will more closely track that which is indicated.
This might be one of the more common reasons to look beyond the most widely seen options, but it is far from the only one. In addition to being rated according to the resistance they add when deployed in series into a circuit, for example, resistors are also classified regarding how much power they can safely handle. Once again, the most commonly available parts will be designed to satisfy the most prevalent needs, but these are not the only ones that can possibly obtain.
As a result, manufacturers also offer power resistors that are meant to be able to withstand much higher currents at a given level of resistance. Making use of a single high power resistor in a circuit that needs it can greatly simplify things and also enable projects that might otherwise be impossible. Whether with a resistor of this kind, one designed for greater precision, or something entirely different like a current sense resistor, what can seem like a simple type of part therefore often turns out to be fairly complex and varied.