This document provides an overview of key concepts for limited energy circuit calculations, including Ohm's Law, Kirchoff's Law, and voltage drop calculations. It warns that the following materials are needed: the NEC codebook, the LERC PDF on calculations, and a calculator with memory and calculation functions. It then reviews Ohm's Law formulas and rules for series and parallel circuits, shows examples of calculating total resistance using both series and parallel resistor combinations, and emphasizes that to fully solve a circuit one must calculate voltage and current in addition to resistance.