One of the most important parts of an electrical circuit is a resistor. Every complete electronic circuit must have a resistor of some kind. 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. Custom resistors are produced to work on custom-made devices. They are also referred to as precision resistors and their function is to provide custom made resistive technology to custom devices. There are some factors that have to be considered when choosing custom resistors. 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. The total resistance will be the value of the custom resistor to use in the circuit. 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.
Another factor that determines resistor choice is the power rating of the resistor. 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.
Resistor construction also determines the kind of resistor to select. Construction in this regard has to do with the type of material used to make it. Various substances are used in the manufacture of custom resistors. These include a metal film, a carbon composition, a foil, a thick and thin film, among many other materials. The material used in making a resistor will dictate how it will resist the current in the circuit.
How the resistor is mounted in the circuit. This factor also has great bearing on how a custom resistor will work. The different kinds of mounting for resistors include surface mount, PC mount, panel mount or bracket mount. The custom device into which the resistor is to be included is the one that determines the kind of mounting adopted. You have to ensure that you get the proper resistor to fit the mounting technique on your circuit.