Resistors play a very important role in all electrical circuits. Any electrical connection cannot be complete without a kind of resistor. 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. These are specifically made with a particular system in mind. The fact that they are very precise and accurate when in operation is the reason they are also referred to as the precision resistors. 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. The total resistance will be the value of the custom resistor to use in the circuit. Resistance is measured in Ohms using an ohmmeter. Once this value has been established, you can then look for a custom resistor that fits it.
The next consideration to look at is the resistor’s power rating. This has to do with the amount of power in Watts that is to 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. If the voltage and the resistance in a circuit are known, power rating can be computed and the value used to select the appropriate custom resistor.
Resistor construction is another factor to consider. 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. Some of them are thick and thin films, metal films, foils and carbon composition. 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 kind of device into which the resistor is to be placed is what determines the kind of mounting to be used. You have to ensure that you get the proper resistor to fit the mounting technique on your circuit.