Resistors are an important aspect of any electronic or electrical circuit. They do not do anything that would stand out within the circuit though. As named they limit the flow of current inside a circuit. This is referred to as resistance and is gauged using Ohms denoted by the Greek letter omega. A resistor limits the quantity of power that gets to the other components of the system. For example if too much power goes into an LED lamp, it will be destroyed. From this functionality it is clear that the resistor protects other parts of the circuit.
Different systems require different levels of resistance. A custom resistor is therefore a resistor made for a specific system. They are designed for different systems and uses. In selecting a resistor for an individual system one should be aware of how high a temperature it can tolerate prior to getting damaged. Resistors heat up when current passes through them.
A resistor which has higher limit will become warmer than one with lower limit. The material used to make the resistor is important as some materials may not be able certain temperatures. A custom resistor should be put together with consideration of heat produced in use.
Tolerance refers to the accuracy of a particular resistor. It is hard to make a custom resistor that would be perfect for a system and the current flowing through it. The measure of tolerance or accuracy of a resistor will be designated as a plus or minus of a specific percentage. For example a 5% resistor with a rating of 200ohms has a limit ranging 190ohms and 210ohms.
Materials for making custom resistors are carbon, metal or ceramic. As noted above resisters build up heat as current flows through them. The material they are made of should be able to withstand the heat without for instance catching fire or melting. Most resistors today are made of metal or carbon.
Resistors are made either surface-mount or through-hole mount termination designs. The main material for Through-hole mount are either made of carbon, metal film or very thin metal foil. The former is usually cheaper than the latter. Surface mount resistors, on the other hand, are normally made from thin or thick metal foil. It should be noted that resistors made of thin foil are low-cost as compared to those made of thin foil. Variable resistors are good option to the static resistors. They can be regulated to work between a range of values. They are also called rheostats and are often used in such components as knobs for volume.