Resistors

Resistors are electrical components that provide resistance in an electrical circuit. When resistors are arranged in series, the total resistance is the sum of all the resistors in the series. When arranged in parallel, the total resistance ( $R$ ) is the reciprocal of the sum of one over resistors in parallel, or $R = (\sum\limits_{i} \frac{1}{R_i})^{-1}$ or $R = (1/R_1 + 1/R_2 + ...)^{-1}$ .