Resistor A passive electrical component with two terminals that are used for either limiting or regulating the flow of electric current in electrical circuits. The main purpose of resistor is to reduce the current flow and to lower the voltage in any particular portion of the circuit. It is made of copper wires which is coiled around a ceramic rod and the outer part of the resistor is coated with an insulating paint. SI Unit of Resistor is Ohm. What is a resistor? A resistor is a passive two-terminal electrical component that limits the current flowing in electrical or electronic circuits. Its property to resist the flow of current is called resistance, expressed in ohm (Ω), named after German physicist Georg Simon Ohm. Resistors are available in different sizes. Its size is directly proportional to its power rating. The power rating is the maximum amount of power that a resistor can dissipate without being damaged by excessive heat build-up. The larger the surface area covered by a