Resistor is the most used component in all electronic circuits and whose main physical characteristic that is the conversion of electrical energy to thermal energy. It can also be said to be an energy-consuming component on account of generating heat after passing through current.

Meanwhile, the resistor also acts as a role of separating voltage and current in the circuit, which means that the resistor separates voltage in series but separates current in parallel. In series, i=I, the current on each load is equal to the total current; While in parallel, u=U, the voltage on each load that is equal to the total voltage.