Considerations for Selecting Custom Resistors
Resistors play a very important role in all electrical circuits. 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.
Variable resistors which have a resistance that can be adjusted, as well as the fixed resistors whose value of resistance is constant, are the two common types of resistors. With the technology changing and advancing every day, there has arisen a need for a third category of resistors, the custom resistors. Custom resistors are produced to work on custom-made devices. 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. Here are some of these considerations.
The necessary resistance for the circuit to operate. You are supposed to know the total resistance for a particular circuit before you choose the resistor to supply this resistance. This will form the value of the resistor that you are going to choose. For you to measure resistance, you need an instrument called an ohmmeter which gives values in Ohms. Once this value has been established, you can then look for a custom resistor that fits it.
Power rating on the resistor is the other factor to consider. The amount of electrical power lost by the resistor in Watts is referred to as the power rating of the resistor. The power flowing through a circuit is a function of voltage, current, and resistance. When the value of the square of voltage is divided by the resistance in the circuit, the result obtained is the power. 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. Various substances are used in the manufacture 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.
Kind of mounting required for the resistor. 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.