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. The role of the resistor is to provide a resistance to the flow of current in a circuit so that the other device is not damaged by an excess 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. There are some factors that have to be considered when choosing custom resistors. Some of these factors are outlined below.
Amount of resistance needed in the circuit. You will have to know the measure of the total resistance in an electrical circuit before selecting a suitable resistor. 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. Only after measuring this resistance will you be able to select a custom resistor that fits into the circuit.
Power rating on the resistor is the other factor to consider. This has to do with the amount of power in Watts that is to be dissipated by 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.
Resistor construction is another factor to consider. Resistor construction deals with the substance used to make the actual resistor. 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 material used in making a resistor will dictate how it will resist the current in the circuit.
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. The different kinds of mounting for resistors include surface mount, PC mount, panel mount or bracket mount. The positioning of the board in the device will dictate which mounting will be adopted for the resistor. You have to ensure that you get the proper resistor to fit the mounting technique on your circuit.