One of the most important parts of an electrical circuit is a resistor. Without the incorporation of resistors, circuits would not be complete and able to convey a current. In order to prevent the damage of other components in a circuit by excess current, a resistor is used to provide resistance to the current.
There are two types of resistors; namely fixed resistors whose resistance doesn’t change, and variable ones whose resistance changes depending on other components of the circuit. With the technology changing and advancing every day, there has arisen a need for a third category of resistors, the custom resistors. Custom electronic devices are the ones that require custom resistors in order to work. They are also called precision resistors by virtue of their precision and high degree of accuracy in their operation. When selecting a custom resistor to use in a device, a number of factors are considered. Some of these factors are outlined below.
Amount of resistance needed in the circuit. Before you select a custom resistor to use in an electronic device, you ought to know the amount of resistance which is necessary for that particular circuit. This value of total resistance is the amount of resistance that should be supplied by the resistor chosen. Resistance is measured in Ohms using an ohmmeter. Only after measuring this resistance will you be able to select a custom resistor that fits into the circuit.
Another factor that determines resistor choice is the power rating of the resistor. Power rating is actually the amount of electrical power, measured in Watts, which will be dissipated by the resistor. The amount of resistance, voltage and current flowing through an electrical circuit will determine the amount of power in the circuit. Power can be calculated by dividing the value square of voltage by the value of the resistor. A suitable resistor can thus be selected if the values of resistance and voltage are known, from which electrical power rating for the resistor will be determined.
You also have to factor in resistor construction when selecting a custom resistor. This has to do with the material from which the actual resistor is constructed. There are different kinds of material used in the construction of custom resistors. Carbon composition, metal films, thick and thin films as well as foils are some of these materials. The effectiveness in resisting a current will normally depend on the material used.
How the resistor is mounted in the circuit. The style in which the resistor is to be mounted into the circuit is also an important consideration to have in mind. Resistors could be bracket mounted, panel mount, PC or surface mount types. The custom device into which the resistor is to be included is the one that determines the kind of mounting adopted. So, ensure that you select the appropriate mounting for your custom resistor.