Looking For The Right Resistor For A Given Circuit And Set Of Desires
In many cases, individual decisions of this kind will turn out to be relatively straightforward to resolve. The most widely available sorts of resistors are that way for a reason, with a broad applicability to many different situations making them common and generally useful. On the other hand, many projects will also involve a need for at least one or a few resistors of more focused and specialized kinds.
For instance, some circuits and devices are meant, by design, to include relatively high amounts of power. In many cases, this will mean a combination of relatively low overall resistance and fairly high voltages, with the figures in question often ranging quite a bit above what the most common kinds of resistors might be meant to handle. When this turns out to be the case, a 120 ohm resistor that is designed to handle many watts of power without overheating or breaking down will often be required instead. Otherwise, a high voltage resistor that stands up to a great deal of electric potential even where wattage remains reasonably low might need to be selected.
In some cases, it will be the method of assembly chosen for a particular project or product that will enforce the need to select a specialized sort of resistor. The surface-mount production technique that is used for many consumer electronic devices and other mass-produced products, for example, will necessitate the use of resistors specialized to accommodate it. Fortunately, surface mount resistors are available in a full range of types and configurations, making the process of selecting one generally simple.
There will also be times when a resistor will be chosen not for the resistance it adds to a circuit but for other reasons entirely. In some cases, for example, resistors are selected to contribute heat that keeps a delicate element warm, while a current sense resistor might be used to monitor the level of that kind of activity. Choosing the right part for a particular circuit can therefore turn out to be fairly involved and challenging.