Resistors play a very important role in all electrical circuits. 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.
The two types of resistors include variable types, whose resistance changes with time and temperature, and fixed resistors which have a fairly constant value of resistance. 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 referred to as precision resistors and their function is to provide custom made resistive technology to custom devices. Certain factors determine the kind of custom resistors chosen for particular circuits. Some of these factors are outlined below.
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. Resistance is measured in Ohms using an ohmmeter. Selection of a custom resistor to fit into the circuit can only be known after measuring the resistance.
The next consideration to look at is the resistor’s power rating. 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. So, once the two values of voltage and resistance are known, power rating for the resistor is calculated, and this information is used when choosing the custom resistor to fit the circuit.
Resistor construction is another factor to consider. 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.
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 various ways in which you can mount a custom resistor in the circuit include bracket mounting, panel mounting, PC as well as surface mounting. The kind of device into which the resistor is to be placed is what determines the kind of mounting to be used. So, ensure that you select the appropriate mounting for your custom resistor.