Resistors are electrical components in a circuit. In a circuit, the resistors may be arranged in series or in parallel. Resistors serve a number of purposes in an electric circuit.First, the resistor may be used to reduce the flow of current in a certain direction of a circuit. As their name suggests, resistors offer resistance to the flow of electric current in a circuit. This is to imply that, if in a circuit that has its components connected in parallel, and in one of the circuit paths we have a resistor with a lower rating and in the other path we have us resistor with a higher rating, current will avoid the path with more resistance and flow through the way with less resistance.
Custom resistors may also be used to divide voltages in an electric circuit. Voltage division can be achieved in a circuit by connecting the circuit components in parallel. As we have already established that electric current usually follows the path with lesser electric resistance, it implies that we will have a different amount of voltages passing through the circuit depending on the resistors that are connected to the circuit. It also ought to be noted that the relationship between the voltage and the current and the resistance in a circuit is that of varying proportions. It is assumed that the voltage in a circuit is a constant whereas the electric current is inversely proportional to the resistance in the circuit.
Resistors may also be used to dissipate electric power in form of heat. In that case, they are used to generate heat in the circuit. Resistors used to this end ought to be those having the highest resistance so that they offer maximum resistance to the flow of electric current. In this way, optimal heat is generated. Resistors having the lowest value of resistance cannot be used for this purpose since they can generate only a very limited amount of heat.
In conclusion, custom resistors may be categorized into two, namely the variable and the fixed resistors. Fixed precision resistors will offer a uniform amount of resistance whereas variable resistors can have the resistance values adjusted according to the demands of the circuit. The choice of either of these two types of resistors is usually informed by factors such as the need for the resistor, the type of circuit, the purpose of the circuit among many other factors.